Problem when changing the velocity of midi notes

Cubase 10 pro:

When I change the velocity of midi notes, the note(s) I change starts playing from the moment I touch the velocity bar (so far normal)
But all the notes that I change keep on playing, No way to stop them from playing.
I have to save the project, close ande re open.
How can I solve this?


Only the very 1st selected should play back. Could you try in Cubase Safe Start Mode, please?