FCPx, clips in timeline went black
I have FCPx 10.6.5. I have been using it for years. Suddenly many clips in the timelines have gone black. I tried relinking but it comes up with an error about incorrect duration, but its the right clip. The clips are still connected, the clip displays in the browser but not in the timeline. If I drag the clip into the same timeline it shows ok. The clips were originally imported in Color Final 1.3.6. I tried trashing preferences and updating, all the usual tricks, but no luck. iMac Retina 4k 21.5 2017. Pro video formats 2.1.2. Ventura 13.3.1 (a)
Thanks,
David