This is a bit tricky to reproduce, but you can repeat it once you understand what happens.
1/ make a new project
2/ add any drum machine you have on an instrument track
3/ insert beat designer on the instrument track
4/ make a pattern in beat designer
5/ disable the track
6/ save project and close cubase completely
7/ reopen the project and enable the instrument track
- the fact that the keyboard midi in is not connected, once the instrument track is enabled has already been reported, same as the midi insert efx that are not loaded once the track is enabled.
- what is different is that the pattern made in beat designer, although beat designer is NOT enabled in het midi insert, is still playing back the pattert, the pattern and beat designer are active somewhere, somehow, but they just are not visible.
solution?: disabling the midi insert (switch off) quits the pattern that is still being played by the removed beat designer