One of my bugs is that fences or redstone dust aren't connected, when i load my world in the new shapshots. When I load it in 1.12.2 it works all as intended. Pictures with coordinates(picture 2,3,4,5): https://imgur.com/a/mCKiv
My world (1.12.2):http://www.mediafire.com/file/mugx846yni1bvy8/New_World_snapshot_3_1_in1_12_2.zip
My world(18w10d): http://www.mediafire.com/file/b2338fw66pn4jc3/New_World_snapshot_3_1_in_10w18d.zip