Clips with WARP TIME don't play back

[skipscada]

So I'm cleaning up the timing of some basslines using warp time as a clip effect. Things seem to work fine, timing gets fixed, but ... (after exiting and re-opening the edit, I think) then the clips with warp time don't play back. And they render as a flat line if I try to render clip. Help?

Investigating a bit, I have found out that if I use the "remove clip effects" action, then undo that action, the warp time markers are restored and the clip plays back fine with warp time. So I have a workaround and the work isn't lost, but obviously something is wrong.

[skipscada]

Noone? Playback with warptime works as expected for all other users at all times?