Originally Posted by Fat Destiny Warrior
An additional reason why people feel PO's RNG is weird compared to the games is because it uses a completey different system of RNG to the games. In PO, you use the rand function, while ingame, you basically start on a particular seed, advance it based on what move you use(I can elaborate if you want)
That rand() function you refer to uses the same seed mechanism.
My friend made a research and proved that pokemon RNG produces discrete uniform distribution of numbers, which means it's equivalent to any other pseudo-RNG.
To make it clear, imagine throwing a coin and rolling a dice: Despite methods are different, you have equal chances of getting heads/tails with coin and even/odd number with dice.