When one of my PCs has attempted to open a Shipment Container (from fulfilling a Crafting Writ), attempted to use a Motif, or attempted to destroy an item (such as Used Bait), then the game client has displayed a UI Error message about EsoUI attempting to access a "private function". For what it may be worth, I believe that I have submitted at least one /bug report while in-game with an attached screenshot for another occasion when the same UI Error message was displayed.
It has also happened when my PC attempted to open a Sealed Master Crafting Writ while viewing inventory with the "All" column, but I didn't take a screenshot and dismissed the error. Subsequently, the PC opened the Sealed Master Crafting Writ while viewing it in inventory in another category, probably the Consumable view.



UPDATE (02/13/2017): For what it is worth, I have found that Awesome Guild Store has problems with the Inventory UI and/or Crafting Bag feature, and I've reported at least one UI Error to the developer
via the ESOU Add-Ons website. I have also made a screenshot of a UI Error caused by Master Merchant when I opened the Inventory to look at and/or interact with items. I've also reported that UI error to the developer
via the ESOU Add-Ons website. That said, neither of the UI Error messages that were displayed for either of these add-ons referred to the function
EsoUI, which the others that I've shown above do.
Edited by Shadowshire on March 6, 2017 5:10AM --- Shadowshire .......... ESO Plus on PC NA with Windows 7 Pro SP1
nil carborundum illegitimi