Fake 100-Peso Bill from a Bank

Guys, I need your expert opinion here. Our company staff had just paid a BIR transaction in one of the banks here at Pasig City. The bad thing was one of the bills was declared fake by the bank. Later, I learned from my colleague that the money came from the bank itself and was part of the P10,000.00 bill the bank issued. Upon asking one of the bank's personnel she said that it was not their responsibility once the bills were out of the bank's premises. Hmnnn...is it true?

Will the adage "let the buyer beware" be used or the banking institution which issued the money be held liable here?

FYI here are the scanned copies of the the fake bill:

fake 100-Peso_front
fake 100-Peso_back