Thanks for the report,

On Thu, Jul 30, 2026 at 03:28:02PM -0400, Jamie Stephens wrote:
> sudo lsusb -v -d 0764:0501
> 
> reports:
> 
> wDescriptorLength     504
> 
> Warning: can't get report descriptor, LIBUSB_ERROR_PIPE
> 
> cannot read device status, Resource temporarily unavailable (11)
> 
> As a result, usbhid-ups is unable to reliably communicate with the
> device and NUT cannot reliably monitor UPS status.
The lsusb failure and NUT seem to be seperate, lsusb failure could
simply be device property.

Few possibilities I can think of worth testing:
1) It may be related to LPM, the device may be advertising this but may
not be handling it properly.
2) Commit 8020c41b39f5 (usb: core: allow ACPI-managed hard-wired ports to power off)
lets acpi managed ports be powered off even if hub does not advertise
power switching. The UPS may be sitting on such port and its power could
be cycled out and leave it in a stale state.

I'm attaching two patches to see if they have any effect, please apply
and test them seperatly and let us know the results.
And, as per Thorsten's advice above, run git bisection regardless.

Regards,
Lovekesh