I have been working with this device for a while without issue and had put it aside for a month. I pull it back out and now I hit this same exact issue. Hold the boot was plugging it in allowed a once time upload but when it was done it failed to reconnect.
Workaround is to set the upload speed to 115200 (default is 921600). This seems to allow normal operation again.
What I suspect has happened is that the serial driver was updated/patched/replaced in Windows causing some incompatibility (a lot of security fixes and patches in the last few weeks from PC maker and Microsoft).