Slimes no longer spawn in flat worlds made before 1.18.0

Mob spawning is enable? 

Yes mob spawning is enable

i tested this bug and i am very sure it's true
no slimes spanw in flat world neither in slime chunks nor swamp boime

Yeah, when I was building a village, there were a lot of zombies invading my village but the iron golems took care of it, but I didn't see any slimes. (This no slimes bug happened like in November 2020)

Affects 1.16.221 Hotfix

Code Analysis: In 1.16.100, the y-level for slime spawning was changed to consider sea level. Specifically, slimes now spawn in slime chunks up to 23 blocks below sea level. On normal worlds, sea level is at y=63 and on flat worlds sea level is at y=5. Clearly this eliminates slime spawning in slime chunks on flat worlds.

Potential Fix: Make sea level data driven. If it was customizable in level.dat, then marketplace creators who create using flat worlds can change the value if they need too.

Affects 1.17.40.20

Affects 1.17.32

I think this is fixed.... in a full release?

This issue isn't fully fixed yet, slimes still can't spawn above y=0 in flatworlds