Problem with APC UPS Model BF500BB

Problem with APC BF500BB UPS
Data sheet available at:
http://sturgeon.apcc.com/techref.nsf/partnum/990-2106B/$FILE/990-2106B_REV03.pdf

Context:
Every time there is a power failure, even if it is very short (less than
a second), the BF500BB starts an alarm (from its embedded piezo) which
emits a continuous tone until I press the power button to turn off the
device. This problem occurs whether the UPS is connected to the computer
by its USB port or not.

Problem:
Of course, there is the noise which is annoying, but primarily there is
the fact that I must shutdown my computer to reset the UPS, even when
the power failed for only a fraction of a second.

Question:
Does anyone have a fix for that?

Thanking you in advance,
Max