Snooze.hibernate() causes Teensy32 to lose serial coms to the bootloader for flashing

[jhgorse]

similar to:
deepSleep prevents loading new code? #35

USB serial coms to the terminal work before and after the Snooze.hibernate() call. Teensy bootloader flashing works prior but not after the Snooze.hibernate() call. Repeatable across several devices and computers. The build environment is Platform IO on MS Visual Code. It is repeated for the Arduino IDE as well.

The error message: Teensy did not respond to a USB-based request to enter program mode.

Building .pio\build\release\firmware.hex
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [===       ]  34.9% (used 22904 bytes from 65536 bytes)
Flash: [=====     ]  51.9% (used 136108 bytes from 262144 bytes)
Configuring upload protocol...
AVAILABLE: jlink, teensy-cli, teensy-gui
CURRENT: upload_protocol = teensy-gui
Uploading .pio\build\release\firmware.hex
Teensy did not respond to a USB-based request to enter program mode.
Please press the PROGRAM MODE BUTTON on your Teensy to upload your sketch.

This is in an assembled unit, so the button press is not accessible.

What do you think might be the issue?

Cheers,
Joe