I've created an adventure map without mods. Problem is that when I die, it randomly crashes the game on attempting to respawn. Sometimes it crashes, rarely it doesn't. I've tested this in multiple areas. I don't understand the logs very much, but it says something about being unable to read an air block's facing direction? The blocks in the logs usually refrer to placed signs in the map, or a chest, or literally nothing.

This map was started back in 1.12 and was opened up in the newer snapshots to convert them. I had also imported region files from old maps, which seem to have imported fine, but this glitch seems to persist in all regions. It's very annoying and unpredictable and breaks the adventure map.

This glitch seems to have started happening when I converted the map from 18W03B to 18w05a.

If it helps, here is the adventure map.
https://www.dropbox.com/s/zrx025s630zr2g6/Atilliary%20Facilities%205%20help.zip?dl=0

The map also uses re-texturing and custom-sound resource packs but the glitch happens without them so I'm ruling them out.

Could I get some in-sight as to what's causing this?