Avoiding Anchor Cycle
 

can this erro be connected with Wykkyd achievement tracked im using?

any clues?

Hard to tell from that error message. The best thing to do would be to disable the addon in question and see if the exception goes away.

This may be an issue with ZOS's code as I'm experiencing it myself without using any add-ons that modify the achievement window. The error seems to occur when you complete an achievement in the category you had open in the window and then open the window again afterwards.