Chatbubble error in shadowlands beta

[siweia]

Attempt to access forbidden object from code tainted by an AddOn
Count: 1
 
Call Stack:
[string "=[C]"]: ?
[string "=[C]"]: ?
[string "=[C]"]: in function `CreateTexture'
[string "@SharedXML\NineSlice.lua"]:75: in function <SharedXML\NineSlice.lua:63>
[string "@SharedXML\NineSlice.lua"]:389: in function `ApplyLayout'
[string "@SharedXML\Backdrop.lua"]:378: in function `ApplyBackdrop'
[string "@SharedXML\Backdrop.lua"]:212: in function `OnBackdropLoaded'
[string "*:OnLoad"]:1: in function <[string "*:OnLoad"]:1>

Has anyone seen any errors like this? It occurs when some chat bubble shows in game, not all of them.
I have no clue on this at all.