It is not fixed, but it was erroneously marked as fixed, and it was listed as fixed in the change-log for Cubase 8.0.30:
I’m using Cubase 8.0.35, and when I disable a track, save project, reload project, and enable the track, I am getting frequent loss of:
– MIDI Input Routings, and
– Expression Map assignments.
It is frequent, but it doesn’t happen 100% of the time.
Numerous other people are reporting the same bug, and they are reporting it here:
In that thread, people have reported this bug as recently as April, 2016, so clearly this bug was not actually fixed in the 8.0.30 update, and it should be marked as not-fixed.
Before it was erroneously marked fix, this bug was discussed in threads besides the official BON-7379 thread:
I put “Disable” in bold, because there was some confusion in the original BON-7379 thread. In that thread, the headline reads “Deactivated”, but later in that thread it was clarified that the problem is with Disabled Instrument Tracks. In the other threads I’ve linked to above, it is confirmed that Disabled Instrument Tracks are the problem.
I have not tried reproducing this in any project containing only one Instrument Track. My projects contain numerous Instrument Tracks, with multiple MIDI Tracks routed to each Instrument Tracks. I often create new tracks and delete old tracks. I mention this in case the process of adding or deleting tracks is contributing to this bug.