The facility is SPAWAR on Pacific Highway in San Diego. The hill where the HRM goes wonky is Presidio Drive. There is probably no connection, but I recall living next to an Air Force base where peoples' garage doors would open mysteriously from time to time.
Since the indicated HR is always slower, never faster, than the actual, I would guess that packets are being dropped between the strap and the computer, but not so many as to make the computer decide that there is no HRM connected.