sound disapeared from timeline - weird error - help?!

[Mark Lewis]

This one is new to me.
1) Open existing project to edit.
2) everything in place, except all clips in the timeline have zero sound - the sound wave area is empty. (show waveform is checked)
3) in my "effects controls" for the clips, all of the audio effects are missing.
4) if I re-drag the actual clips to the timeline from the project panel, the clips I drag have their sound, so the loss seems to be specific to the timeline.

So, I don't know how to fix this. If y'all have a suggestion, I'm all ears. My latest backup doesn't include the 3-4 hours from today - so it isn't worth going back to.

any help is much appreciated.

As a workaround - I double click all the individual clips in the timeline (one at a time), then look at the in and out in the source monitor, then re-import the clip and maually add the in/out then piece in back together.