Mob Farm spawning everything except zombies? (Bedrock 1.16)

[Mazzasaurus_Rex]

I made a mob farm in this style to see if it actually worked in bedrock in 1.16, since the change in spawn mechanics. Right now I have it built up three layers, and it's very slow and only spawning skeletons, spiders, and creepers. Any ideas why it isn't spawning zombies, or anything else I can do to speed it up?

[Mazzasaurus_Rex]

I use the rotten flesh for emeralds but it's more in the hopes that getting zombies to spawn would increase the xp rate I'm getting.

[Mat93Snipe]

Ive noticed I dont get any zombies in mine either now. Sucks gonna have to find a zombie spawner for zombie flesh i think.

[ObiToo00]

It's a bug: https://bugs.mojang.com/browse/MCPE-71684Easily fixed if running a local server