Too short (32 bit) RNG (Random Number Generator)
Aristocrat MK IV cabinets were developed on a 32-bit ARM 250 processor. If the slot developers decided to also use a 32-bit random number seed, then there are just 4,294,967,296 possible RNG states. It may look like a lot, but current computers are very fast and this number of options can easily be examined by brute force (taking a few seconds on a regular laptop).
However, this option could be less likely. Moreover, a 32-bit random number is too short to cover all possible results in some games (5 reels * 90 symbols).