[MC-137773] Fence spawning with it looking like it is attached to something even though its not

I found an abandoned Mineshaft and this fence spawned inside of it with its 'attached arms' out yet there was nothing connected to it.

Linked issues

Duplicates MC-123087. If this world was created after 1.13-pre7, please provide the seed and coordinates so we can try to reproduce the issue.

The Seed is:-205396693175326374

(I created this world in the snapshot 18w43b btw)

The Coords are: -187 31 -163