Here's my walkthrough
MC 1.12.2
Forge 14.23.0.2503
Minecolonies 0.8.4565

I tried to baker see furnances in bakers house but he didn't see them.
Also i tried to recall him\replace furnances\repair house but it not worked.
https://youtu.be/9Eg0HWyXyZE

Updated to last one
got it, sorry. he repairs hut and it goes to work.

Furnances when you paste from gamemode and when it built by builder are different.

Also some minor bug - baker don't care where he works, i think its not normal)

Also after restart baker come insane and just walk around with bread in hand

Did you let the builder repair the hut yet?