Changing Tempo Results In Incorrect Playback?

I’ve found several times that if I change the tempo of a track manually (using the tempo value in the transport bar) that I don’t get the expected result being played back. Today I found that when I drop the tempo from 175bpm to 120bpm, I am hearing notes playing from a VSTi that has no part info or midi triggering in the region of the track I am looping. e.g. I loop 4 bars at the point of bar 100 in the composition and I am hearing notes playing from a particular VSTi within that loop that don’t exist. If I then switch the tempo back to 175bpm again, the notes don’t play.

It is as if there is a unique tempo somehow for the VSTi instrument track that is independent of the rest of the composition - I’m not sure how else to describe it.

Is this a bug? Or maybe some strange feature I am not aware of?

I am using Cubase Pro 9.5 - latest on Win 10. Cheers

Aha - it was because the part was frozen and the system doesn’t adapt the frozen waves appropriately after a tempo change and also doesn’t warn when the change is made.