On a Mac, Mojave, PM6 build 3331. I believe this bug has existed for years.
If you rename a folder in the finder while it is open in PM the folder behaves oddly in PM with images going grey if you try to click on them to view them in one up and some but not all of the other images in the contact sheet go grey. If you leave the PM window open and drag the renamed folder onto the open window it doesn't update. Cmd / doesn't work either. To get the folder to display properly you have to make a new window or tab. I recognize that this is probably as much to do with the OS as with PM, but it would seem that there could be a more graceful outcome. Thanks. Great product.