Get this some times, when i open some crafting skills in AdvancedTradeSkillWindow.

This is with the most recent version? The crafting addition checks for null there so it would have to be the tooltip extension ... maybe if AdvancedTradeSkillWindow does some sort of tooltip parsing using the gametooltip.

Yes, this is the most recent version of Aux and AdvancedTradeSkill from https://github.com/laytya/AdvancedTradeSkillWindow-vanilla . I only get it some times, mostly when i open Tailoring or First Aid. I also got https://github.com/laytya/LilSparkysWorkshop-vanilla that adds adds auction-derived pricing information for trade skills right into the trade skill recipe frame.