in Lightroom Classic (latest version) I have a folder with some bougth development presets. When I hover over the preset-names I can watch the picture on the screen changing accordingly. But - when I cklick on some of the presets (not all) the picture changes accordingly, but as soon as I move the mouse away from the picture the development settings are obviously not accepted and the preview shows a different look. Hope this is understandable... What can I do please? Thanks.
LR sometimes soils its preferences file, and resetting it can fix all sorts of wonky behavior -- you never know which problems it might resolve. That article explains how to restore the old preferences if resetting doesn't help.
Be sure to include the first ten lines of the menu command Help > System Info. Upload one of the problem presets and a photo that shows its misbehavior to Dropbox or similar, and include the sharing link. That will help Adobe reproduce the problem (if they can't reproduce it, it's unlikely they'll pay attention).
John, thank you so much for looking into this! Steps 1. to 3. did not solve the problem. For the measures in step 4. I simply do not have time, keeping in mind that Adobe only looks into it when they are able to reproduce the behaviour... also I do not want to apply for a software testers job ... Thanks again for zour help!