I've occasionally been getting LUA errors in combat since 9.2.5, finally was able to get a taintlog for them and it's pointing to BigDebuffs, there was too much text just related to the event at 23:09:16.902 so I've only included the first handful of blocks. I'm going to try disabling the add-on next raid and see if I still get errors, I'll follow up after that one way or the other.

8/17 23:09:16.902 Execution tainted by BigDebuffs while reading INTERFACE_ACTION_BLOCKED_SHOWN - Interface\FrameXML\UIParent.lua:5751 DisplayInterfaceActionBlockedMessage()
8/17 23:09:16.902 Interface\FrameXML\UIParent.lua:1804
8/17 23:09:16.902 CompactRaidFrame24:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:158 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 An action was blocked in combat because of taint from BigDebuffs - CompactRaidFrame24:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Execution tainted by BigDebuffs while reading INTERFACE_ACTION_BLOCKED_SHOWN - Interface\FrameXML\UIParent.lua:5751 DisplayInterfaceActionBlockedMessage()
8/17 23:09:16.902 Interface\FrameXML\UIParent.lua:1804
8/17 23:09:16.902 CompactRaidFrame24:SetPoint()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:161 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:158 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 An action was blocked in combat because of taint from BigDebuffs - CompactRaidFrame24:SetPoint()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:161 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Execution tainted by BigDebuffs while reading INTERFACE_ACTION_BLOCKED_SHOWN - Interface\FrameXML\UIParent.lua:5751 DisplayInterfaceActionBlockedMessage()
8/17 23:09:16.902 Interface\FrameXML\UIParent.lua:1804
8/17 23:09:16.902 CompactRaidFrame13:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:158 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 An action was blocked in combat because of taint from BigDebuffs - CompactRaidFrame13:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Execution tainted by BigDebuffs while reading INTERFACE_ACTION_BLOCKED_SHOWN - Interface\FrameXML\UIParent.lua:5751 DisplayInterfaceActionBlockedMessage()
8/17 23:09:16.902 Interface\FrameXML\UIParent.lua:1804
8/17 23:09:16.902 CompactRaidFrame13:SetPoint()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:161 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:158 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 An action was blocked in combat because of taint from BigDebuffs - CompactRaidFrame13:SetPoint()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:161 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Execution tainted by BigDebuffs while reading INTERFACE_ACTION_BLOCKED_SHOWN - Interface\FrameXML\UIParent.lua:5751 DisplayInterfaceActionBlockedMessage()
8/17 23:09:16.902 Interface\FrameXML\UIParent.lua:1804
8/17 23:09:16.902 CompactRaidFrame10:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:158 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 An action was blocked in combat because of taint from BigDebuffs - CompactRaidFrame10:ClearAllPoints()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:157 FlowContainer_DoLayout()
8/17 23:09:16.902 Interface\FrameXML\FlowContainer.lua:17 FlowContainer_ResumeUpdates()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:185 CompactRaidFrameContainer_LayoutFrames()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:130 CompactRaidFrameContainer_TryUpdate()
8/17 23:09:16.902 Interface\AddOns\Blizzard_CompactRaidFrames\Blizzard_CompactRaidFrameContainer.lua:57 CompactRaidFrameContainer_OnEvent()
8/17 23:09:16.902 CompactRaidFrameContainer:OnEvent()

I have been getting LUA errors during fated raid bosses with the fated powers Protoform Barrier and Chaotic Essence only. The in-game error didn't specify an addon, but the taint log showed similar to what you have here. Disabling BigDebuffs stopped the error frame in game.

I've been getting all these errors too. It also completely breaks my raid frames during the Lords encounter in SFO. I have to disable BigDebuffs during raids.