Do you have a DGN you can post so I can take a loo? I sounds like the nodes are some how disassociated from the type.
Have you tried changing the Feature Definition assigned to the node and then change it back to see if the FD could resync with the node and allow you to pick it?
Have you tried changing the Feature Definition assigned to the node and then change it back to see if the FD could resync with the node and allow you to pick it?