In my survival world, after a xp-grind at my endermen-farm, while I was under Bad omen, I left the End and to my surprise the Bad omen effect dissappeared without triggering a raid.

How to reproduce:

• Find a stronghold
• Go to the end
• Kill the enderdragon (and the crystals of course)
• do /effect give [playername] minecraft:bad_omen 10000
• /gamemode survival
• Go through the end portal to activate the credits

I think it is no bug of big importance, but I like to see it fixed. Unconfirmed for other statuseffects/potioneffects.