Sanguini’s suggestion on this page seems to have worked for me:
Quoted:
Solution:
- Delete all existing loadouts.
- Create a new loadout for each spec you want to use.
- Highlight the loadout, and you’ll see a settings button. Click it.
- In this menu, select “Shared Action Bars”. Make sure you do this on all loadouts you’ve created and in each spec you care about.
- Try adding some SPEC (Not class) abilities on your current action bars. Then, switch specs to test out if they stick this time.
Hope this helps, it worked for me.