2008/6/11 Gavin Hurlbut <gjhurlbu@gmail.com>:

...
Tue Apr 22 17:58:12 UTC 2008 / Arjen de Korte <arjen@de-korte.org>

- drivers/usbhid-ups: only check once for input reports in
upsdrv_updateinfo() to prevent lockups if the UPS floods the
driver (some Tripplite units will generate one each time you
ask them) [ backported r1450 ]

I don't recall the exact history, and Arjen will soon be on paternity vacation, so I don't want to bother him too much. But it seems you found the solution.

To validate this, you can try the sid package:
http://packages.debian.org/sid/nut

only x86 and amd64 are available ATM.

So I guess the end result is: this bug may be fixed in the upstream,
but ubuntu doesn't have the fix in yet? I also noticed that intrepid is
so far using the same version as hardy.