The fake bills are from North Korea. American money in $100 denominations is carefully scrutinized in the PRC. They know what’s going on.
I’ve heard the NK origin stories before too. It’s not that hard to print fakes. Luckily it’s hard to spend cash here in the good-ole US of A. Otherwise every 14 year old boy with access to a scanner and an inkjet printer would be a millionaire.
I guess it’s not as difficult to spend cash overseas.
I’m a printer and I have people ask me once in a while how hard is it to counterfeit? I ask them who are they trying to fool? The checkout clerk at the gas station, or the Federal Reserve? It’s not making the fakes that’s difficult. It’s spending enough of them before you go to jail to make it worth doing that is difficult. They will catch you. You will go to jail. It’s just a matter of time.