FIFA and Flashback, but NOT on the A600s and A1200s, I think. Something about the ports being different? Toni?
Buttons 2 and 3 are connected to Paula's IO-ports. I don't think there are hardware differences because Paula has been the same since A1000.
Maybe game has strange bug or newer Kickstarts set wrong io-port mode (output instead of input) or something like that?
Button 1 is connected to CIA-A.