Make sure you have not updated these assets. <kuid2:44179:60013:3> Coal and <kuid2:61599:60006:4> Steel rods 10m. If you have then delete the update. The update to these will not work in MPS. It has been reported.
Actually no. The red overlay is when your client does not reflect what's on the server (so there is a sync issue).
Temporarily locked sections are indicated by a red line on the ground, and if you are not permitted to edit you get a message when attempting to edit (you can also view your permissions in the menu).