Hi scheffkoch,
sorry you're encountering this issue.
i tested this in osx 10.12.6 on live 9.7.5 64 bits with stage version 1.2.1.1192, no issue for me here. Vst2 and Audio Unit are fine.
could you please confirm your exact osx and Live version?
i supposed you have an expression pedal on your controller, is there any special settings on it ?
i invite you to try to stage 73-V to version 1.2.1.1230 we released today to check if it solves your problem.
looking forward to read you.
best