While in a Creative Multiplayer world me and another user left the world online for the night (irl), when we came back we had a lot of debuffs. A fix for this would be to test for a player's current gamemode, if it's Survival or Adventure (or not Creative and not Spectator) then the rules of the mod will apply, when a player is in Creative or Spectator the rule will pause until the user is no longer in Creative or Spectator mode.

Sorry for the late reply, I've been busy IRL lately. Good catch, should be an easy fix! :)

Should be fixed by 8c479ca

Although only partly, when you're in creative/spectator mode for a long time and switch back to survival, you'll still get a long debuff period. This is due to Minecraft's Time since last slept stat counting up nevertheless, we might have to replace it with our own custom solution in the future to avoid this issue

Please try out 0.6.0!