External Drive spins down 20 minutes into ripping

[DistinctRecord0]

Hi,
I'm struggling with ripping any UHD disc at all.

Problem is, the ripping always "fails" at around 20-25 minutes. The drive slows down and never spins up again, leaving MakeMKV in the process of reading the disc indefinitely.

I've got an ASUS BW-16D1HT with 3.10MK firmware and an LG BH16NS55 with 1.02 firmware.
My only option is to use them externally.
I've tried 2 different USB to SATA adaptors, both of which recognize the optical drive. That said, they're no 5.25" enclosures, but intended for 3.5" hard drives.

Both USB Adaptors have an external power brick, so I'm wondering how it's supposed to be a power issue.
I've even tried ripping to a slow drive so the UHD drive barely hits 20 MBps to no avail.

Search results for this behaviour didn't help, so any clue at all is much appreciated.

Cheers