HandyNotes-BattleForAzerothTreasures blocks me from upgrading items in Shadowlands. Using version f0bc24b on Shadowlands.

1x [ADDON_ACTION_FORBIDDEN] AddOn 'HandyNotes_BattleForAzerothTreasures' tried to call the protected function 'UpgradeItem()'.
[string "@!BugGrabber\BugGrabber.lua"]:519: in function <!BugGrabber\BugGrabber.lua:519>
[string "=[C]"]: in function UpgradeItem' [string "@Blizzard_ItemUpgradeUI\Blizzard_ItemUpgradeUI.lua"]:104: in function OnConfirm'
[string "@FrameXML\StaticPopup.lua"]:325: in function OnAccept' [string "@FrameXML\StaticPopup.lua"]:5137: in function StaticPopup_OnClick'
[string ":OnClick"]:1: in function <[string ":OnClick"]:1>

It's a taint issue, and it's not happening to me. Suggests it might well be one of those issues where either it is my fault but it's triggered by something that doesn't happen immediately and so is hard to test for, or it's something well down the route of world-map taint that's not me-specific.