Fake Chinese Cash? I Hope Not!

Your coin appears genuine to me. This is perfectly normal. A lot of alloys that "aren't magnetic" in everyday observation (i.e. they won't stick to a fridge magnet) will stick to a rare earth supermagnet.

The Chinese made their cash coins out of mostly copper, but what is left over from the "mostly" could be anything. Some Chinese coins are naturally high in nickel (even though they lacked the technology to identify and separate it) while others have simply been diluted with a small amount of iron; such alloys are likely to be very weakly paramagnetic. Even some alloys that contain no iron, cobalt or nickel can be very weakly paramagnetic, and thus stick to a very, very strong magnet.

I remember having the same "ooh, wow" moment when I passed a supermagnet over my Ancient Roman coin collection, and a few of them stuck. Particularly the "late roman bronzes".

Supermagnets are also great for observing diamagnetism, since they are strong enough for diamagnetic effects to become visible. Silver coins are an excellent way to demonstrate this. Take a large silver coin, and pass a supermagnet back and forth across it. The coin won't "stick", in the usual sense of a nail sticking to a magnet, but the silver will seem to "grip" onto the magnet as you move it, resisting you moving the magnet. And the faster you try to move it, the stronger it seems to "push back". This effect is known as eddy current braking.

There are a number of videos on YouTube regarding coins and magnets. Some are pretty interesting with Chinese coins.