Zombie Villagers not spawning as the correct biome variant. All only spawn as plains zombie villagers.

I noticed this while I made a base in a Savanna, that zombie villagers naturally spawn as only the plains variant zombie villagers, even if they spawn in a place such as a Savanna, where they should be a Savanna variant zombie villagers (same thing goes for Ice, Jungle, Taiga, etc).

I reproduced this by using villager and zombie villager spawn eggs in creative in a Savanna biome, where the same thing happens if you use their spawn egg; they only spawn plains variant zombie villagers, no matter where you spawn them. Spawning normal villagers still spawns the correct variant; the problem is only with zombie villagers. (See images). A zombie villager also still shows the correct variant when infected by a zombie, so I suppose this only involves spawn eggs and natural spawning (ex, savanna villager killed by a zombie still becomes a savanna zombie villager).

This could be a problem, as making swamp and jungle-themed villages is now impossible since villager variants of those types spawn as only plains villagers, and there's no way to acquire one anywhere else.