Bug description
no doubt there is more to it than this but this is what i'm noticing to report:

identity-1.13.2-1.16.5
Origins-1.16.5-0.7.3
fabric-api-0.42.0+1.16

when a merling (only able to breath in water, suffocates on land) transforms into a cod/dolphin (maybe anything else[other identities are untested]) they can now breath on land... also when they change back they're still able to breath on land. relogging doesn't remedy this.

A description of what you expected to happen and what actually happened.
the "breath in water" power should persist

logs and console do not report anything pertinent

update on this, i need to test some more because it now seems like a non-issue

ok right so...
the issue is real, i thought whilst testing there the air bubbles vanishing was me running out of breath but actually that was just a visual.
changing into a cod for example allows one to jump onto land and now breath air, when on land and unequipping the cod identity they're still able to breath air, now they can breath in air and water.

going back under water after unequipping shows no air bubbles overlay but after some time (assuming amount of time it would take for air to run out) the bubbles overlay returns and things appear to be reset back to normal (able to breath under water but not on land again)