Images all showing as greyscale

We opened up a client catalog today and all but a handful of images had turned to greyscale. Now they are all greyscale. No styles applied. There was an update available which we applied and for a moment, on relaunch, the images showed correctly. Then they flipped to greyscale again. We opened a second catalog and the same thing happened. Can't find any settings or edits that might have changed things. Rebuilt previews, no change. Running Monterey on Mac mini M1.