Samper automation control shows "-nan(ind)" and doesn't work

I have a track with a Cubase Sampler and automation of the COARSE PITCH dial.
It worked for a bit but then two strange thngs happened:

1st - the automation lines between the dots on the arrangement window became invisible until zoomed right in

2nd - the automation stopped working and the control couldn’t be moved manually any more on the sampler … the value showed “-nan(ind)”

Please help, this is a disaster for an absolute monster of a track I created.

Screenshots below: