LR 7.3.1 hangs when camera is disconnected

I connect my camera to the computer via USB cable, import my pictures through LR & add them to the computer hard drive. After the import, LR "ejects" the card. If, after that (files are already copied to hard drive) I turn off my camera, LR hangs.

I just had an online session with your support and they re-installed the software, but it had the same result.