Village town centers aren't affected by jigsaw pools

Datapacks can be used to modify jigsaw pools. However, they do not affect the town centers for some reason. 

I made a datapack that generates bamboo in the features and I tried to make all town centers generate as a zombie village. However, the bamboo generates but the town center remains the same.

 h3. How to reproduce

1. Download the data pack zombievill.zip and add it to a new world
2. Find a village

   /locate village

3. We expect to see a zombie village variant, but we get a broken village.

There are weird errors in the log:

Unknown tag: aei@78055a51

Input does not contain a key [element_type]: MapLike[{}]