https://www.youtube.com/watch?v=HqyQuNLUS_U

Managed to record it happening during raid. The footage in the vid is in chronological order.

1st clip I change from Arms to Fury, pull the boss only to find doing this swap bricked the action bars.

2nd clip I /reload it fixed the bars, I swap from Fury to Arms, this bricks them again, I /reload and it does not fix them this time. I swap back to Fury, bars are fine, change to a different talent build and it bricks them again.

3rd clip I disable Dominos, bars are fixed again.

Im not sure what is causing this, or if the issue is with Dominos or Talent Loadout Ex or maybe both.

Do you get the same behavior if you switch talents while using the stock action bars?

Generally, Dominos doesn't have any control over the contents of the action bars, just placement and paging settings.

Ive not yet had this happen using stock bars. This is the reply I got from the Author of Talentloadout ex
that suggests they have had this happen with stock UI so I am not sure.

"Talent Loadout Ex does not change the action bar, unlike the default loadout system.
In my environment, changing the specs sometimes breaks the action bar. This happens regardless of Talent Loadout Ex.
I cannot figure out why the action bar is broken.
So I created a backup of the action bar for each spec in the default loadout system."