Audio tracks that have been imported via 'Track Archive' to Cubase 10.5 lose their routing and appear as 'Not connected'.
For now, routings of tracks included in a track archive can only be restored if the archive also contains the corresponding audio tracks used as routing source or destination.
The problem can only be avoided by including audio tracks/groups that are the routing source or destination of other tracks in a track archive export. Otherwise, routing has to be restored manually after importing the track archive.
Example: If an audio track is connected to a group channel, the group must be included in the track archive.
We are working on a permanent solution!