I've got several scripts that use mpv to display pictures.

It used to be that I could ^Z and fg on those scripts without any issues.

For a few weeks/months now, it seems to be broken. I have zero idea if
this is an issue with mpv, ksh, or signal handling.

I think mpv gets into another process group for whatever reason ?

It still gets suspended, but TCONT doesn't do a thing.

Rings a bell ?