Not sure if it's your mod or another mod messing with it but whenever I die and go to swim again, character just freezes. Can't move or anything and the o2 meter is permanently set at 0 so I die again. This issue disappears when I go to title screen and reload the save rather than respawn.

So i tested it and it is my mod. Still i would appreciate it if you could try to reproduce the bug with only my mod installed before opening an issue.
But until i release a bug fix you can equip an item (helmet, chestplate, leggings or shoes) after dieing. It can be any armor item and you can unequip it instantly. That would be faster than going to the main menu.

OK.

Fixed in v1.3.81.