1. When you move them to the session layer, do you make sure the "Bound Layer" is also the session layer? I've found this to be an issue if it's not.
2. Did you zoom out to map view? I had a similar issue with a 12 session ported into TANE. Train invisible at ground lever, but around 2000 ft up it showed up. I was able to delete and replace it.
3. Did you look for the consist with CTRL+F? I could "find" mine in the right place though it couldn't be seen.
Are we having fun yet?\
:B~/