there aren't many other software bugs in casinos that affect the money. They're usually graphics-related or crashes, and they usually just restart the machine and write a bug report.

If they are related to money, they pull the machine out of the field until a new software version is fixed. A gaming company I used to work at had an issue with multi-jurisdictional machines that worked in Mexico but could display english or spanish. The machines could also change denomination, say from $0.05 to $0.25. There was some bug where if you reset the power, you could get it to bump your credits up from 20 nickels to 20 quarters (or might have been 20 pesos to 20 cents), it was something dramatic and easily exploitable that was fixed promptly.