I am encountering the following error since patch 10.2, primarily when attempting to interact with items in the inventory (i.e., right clicking on them), but the same issue also occurs when attempting to upgrade items and other forms of inventory interaction:

1x [ADDON_ACTION_FORBIDDEN] AddOn 'ChatCleaner' tried to call the protected function 'UNKNOWN()'.
[string "@!BugGrabber/BugGrabber.lua"]:481: in function <!BugGrabber/BugGrabber.lua:481>
[string "=[C]"]: ?
[string "=[C]"]: ?
[string "=[C]"]: in function `UseContainerItem'
[string "@FrameXML/ContainerFrame.lua"]:1424: in function `ContainerFrameItemButton_OnClick'
[string "@FrameXML/ContainerFrame.lua"]:1476: in function <FrameXML/ContainerFrame.lua:1463>

I haven't been able to figure out if there is a specific action that triggers this behaviour, it just happens during the course of a play session and requires an interface reload to get the inventory into a workable state again.