if you have an effect on the player then update to todays snapshot it will remove the effect. This is probably unintentional.
MC-264750
Effects are lost when updating to 23w32a
Resolved
Fixed
0
Missing upgrade path, indeed a mistake/not intentional.
Might be good to check custom potions/arrows, area effect clouds, suspicious stews and mooshrooms to see if any of their changed data is forgotten as well.