missing files after pitch shift

Hi there. I was working in a very simple project, then pitch shifted a few regions – and then when I tried to open up the session again a few minutes later, the pitch-shifted regions were gone. I got the ‘[WARNING]: A sound file is missing. It will be replaced by silence.’ text for a few files.

All I did was a pitch shift, and nothing else… Has anyone else had this issue after pitch-shifting? Is it a bug? Are those WAV files actually gone?

I’ve had this problem before when WAV files suddenly disappear, albeit in older versions of Ardour, but honestly, it is an awful feeling to be constantly worried your DAW is going to eat your files. I am willing to take any steps necessary to prevent this from happening, if anyone can offer their suggestions… Thanks for your help. I appreciate all of the time and effort people have spent working on this program.