How to reproduce?
Give yourself any effect with a level >= 128: /effect give @s jump_boost 999999 128 true
Leave and rejoin the world.
Now the potion effect acts as if it were level 1 when it is supposed to act differently at level >= 128.
For example the jump_boost effect at level 128 prevents the player from jumping. But if the player leaves and joins the world, they can now jump as if they had the effect at level 1.
If you put a level 128+ resistance effect on the player it is impossible for them to take any damage. But if they leave and join the world they will now be able to take damage as if they had the resistance effect at level 1.
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Comments 6
Yes it does, you're using unsupported amplifiers, that's the parent report for all issues with unsupported amplifiers. (You edited the report since my comment.)
Post-edit: cannot reproduce.
At the risk of repeating myself. It has nothing to do with MC-10755. It is another bug. Because the effect works in a certain way when you give it to the player and doesn't work anymore if you reload the world.
Specifically the game does not save the player's potion effect level if it is above 5 and sets it back to 1 when he joins the world. This is not an expected behavior.
That the potion effect doesn't work as expected and is no longer supported above 5, ok. This is even cool because it allows things that would be impossible without it. But this is something else.
MC-118857 then.
Duplicate of MC-10755, unsupported amplifier.