Music tracks reset upon restart of PP

Hi,

I'm having a problem where after I saved my work the day before, upon reopening the sequence, the music track, which is generally on track 2 of the audio, has reset after I had used the remix and stretch tools to set it correctly on the timeline. This has just recently started to occur. The main audio on track one is ok. Is it something within the remix and stretch tools causing this? I have to delete the music, reintroduce it, and then set it up again. Any help would be greatly appreciated.

The image attached shows how it looks after starting PP.

Thanks

John