Every time I log in, Respawn due to death, zone in and out of Arena, BG, Delves, Zones the UI changes. I have to click either classic or modern than back to my saved UI. This has been happening since the anniversary patch. I have 0 addon’s and it happens on so far every character I log into.
I had that issue for weeks. Yesterday it finally resolved. Not sure if it was because I downloaded a mod called hekili or because after I downloaded the mod I pulled my action bar one lower and each of the corresponding action bars after the first one so i could see the addon icons. So Try within your preferred ui save to move the action bar 1 lower and then re line up the rest and save. I wouldn’t have thought that would fix mine as id given up trying but it did work for me after that.
Still happening.
Moving the action bars one space and re-saving my main’s profile worked for me. It is also working on my alts using my main’s profile. So far, anyway!
Thank you for the info but, I have tried that and even creating a brand new layout. Still the same thing.