I think this might be a recent regression.
I've been playing with raid frame anchor "RIGHT" since shadowlands beginning, and never had this issue.
Sometimes when my teammates get crowd controlled, the big debuff is anchored to the exact center of the raid frame.
In addition, 6 buffs get onto one row instead of 3 icons * 2 rows.
This doesn't always happen but it's pretty frequent. It's annoying since I'm used to checking the right side of raid frames for dispelling.

Confirmed, some variation of this happens to me too, I also have my anchor said to RIGHT and since the new update it occasionally reverts back to the default position and loses its functionality, size goes back to normal and max buffs doesn't exceed 3.

Got these lua errors just now, which might be related (since my buffs are also messed up):

Message: Interface\FrameXML\CompactUnitFrame.lua:1405: attempt to index local 'buffFrame' (a nil value)
Time: Fri Mar 25 00:00:07 2022
Count: 15
Stack: Interface\FrameXML\CompactUnitFrame.lua:1405: attempt to index local 'buffFrame' (a nil value)
[string "@interface\FrameXML\CompactUnitFrame.lua"]:1405: in function CompactUnitFrame_UtilSetBuff' [string "@Interface\AddOns\BigDebuffs\BigDebuffs.lua"]:1520: in function func'
[string "@interface\FrameXML\AuraUtil.lua"]:43: in function <Interface\FrameXML\AuraUtil.lua:38>
[string "@interface\FrameXML\AuraUtil.lua"]:58: in function ForEachAura' [string "@Interface\AddOns\BigDebuffs\BigDebuffs.lua"]:1502: in function <Interface\AddOns\BigDebuffs\BigDebuffs.lua:1448> [string "=[C]"]: ? [string "=[C]"]: in function CompactUnitFrame_UpdateAuras'
[string "@interface\FrameXML\CompactUnitFrame.lua"]:94: in function <Interface\FrameXML\CompactUnitFrame.lua:45>
[string "=[C]"]: ?

Locals: buffFrame = nil
index = 4
name = "Rejuvenation"
icon = 136081
count = 0
debuffType = "Magic"
duration = 17
expirationTime = 1301223.122000
unitCaster = "player"
canStealOrPurge = false
_ = false
spellId = 774
canApplyAura = true
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = "attempt to index local 'buffFrame' (a nil value)"

This seems to have something to do with fighting players coming out of stealth, and might not be the cause of this anchor issue exactly.

Is this still occurring in v10.11? It may have been related to #348

@jordonwow Thanks for the info, I just updated the addon and will keep testing.
When the weird anchor happens, I didn't see any LUA errors, so I'm not entirely sure if it's the same thing.

Still happening with the latest version:

Quite frequently inside arena.