Fenix 5 Plus keeps rebooting itself when connected to PC and Garmin Express 6.19.2.0

Since update to Garmin Express 6.19.2.0, when my watch is connected to my PC it keeps rebooting itself. Everything else seems to work normally. I have already tried the usual reboots, uninstall and reinstall Garmin Express. Any ideas / suggestions? Are there any cache / temporary files that may be stuck I can delete? Watch stays on if connected to the PC without Garmin Express running, and I can see it and its folders in Windows Explorer. Thanks.