BIOS 3.09 did not fix my issue. I’ve had my 250GB connected through a USB-C card for about two days, and it just dropped and reattached.
My overall experience has been that this is independent of charger connectivity, storage card location, and other attached peripherals. Sustained reads seem to trigger it more often than when it is left idle, but it will still trigger at idle (such as this most recent one).
Batch: 6
CPU: i5-1135g7
RAM: 1x16GB
HDD: 2TB SN750
BIOS: 3.09
OS: Win10 Pro
Expansion Cards+connections (clockwise from back left):
Full Power Magnetic Charging Card → charger
USB-C → storage
USB-C → Ethernet hub → peripherals
USB-C → TB3 cable → ADT-Link R43SG-TB3 → GTX1650S