Unsure if this is specifically with Swarmblade Form or just shapeshifting in general, but occasionally when changing zones (that’s not a town hub) in Swarmblade Form all skills on the action bar shift to the left by one and right-click is unassigned. If I zone back to a town I return to human form and all original skills are removed from the action bar. Reassigning the skills fixes the issue temporarily. Seems to happen every other instance/zone change.
similar issues here with Spriggan Form. On zone transition, transformed skillbar loses the shift back to human skill, usually replacing the right click with whatever was in that slot in Human form. This makes it impossible to transform back without spending all your rage, but also sometimes gives access to normal skills while transformed (Fury Leap is kinda nice to have in Spriggan Form )