Since installing Lightroom Classic 10.0 (or maybe it started with Mac Catalina) whenever I select a photo in Library and then change to Developer, the wrong photo opens. Instead of the photo I selected, I see the first photo in the current collection, e.g. "Precvious Import", or "All Photographs". If you are editing the Previous Import set, this is a minor annoyance, but if you are editing a photo in the All Photographs set, getting back to the correct photo is all but impossible. I don't see any reports of this as a bug, so I assume it it some setting I need to change. But I can't see anything useful in Preferences.
If you go back to Library mode, the picture you previously selected is still selected.