The bug is this: the woodland mansion is totally corrupted, as can be seen in the screenshots. only some of the blocks are there, and glass, for example, doesn't connect, but is just pillars next to each other. Just look at the pictures, it will explain everything there is to say. I think it has to do with the new block values and that the woodland mansion isn't updated to these values yet.
MC-122224
Woodland mansion bug 17w47a
Resolved
Duplicate
0
Lenard van der Maas
(Unassigned)
Unconfirmed
Minecraft 17w47a
Retrieved
Duplicate of MC-122174 – If you have not, please use the search function in the future, to see if your bug has already been submitted.