Forge Mode problem

I began making a custom map on parallax.
everything was going great. Had finished the level path and was going to work on walls.

I saved it and exited out to go eat, but when I came back and loaded up the map, some of the items where untouchable. Permanently locked. I could touch them in Spartan mode, but couldn’t clamber on them. When in monitor mode, the cursor wouldn’t read anything was there yet I could bump into it.

What has happened that has caused this? I don’t want to start over on this map. It’s huge.