It was a rumor that existed for several years, but it finally proved, The Street Fighter II (CPU) computer cheated when it fought.
You must have felt on more than one occasion that the computer was responding faster than anyone, and even striking out of nowhere, well now, according to youtuber fighting games and combos specialist Desk, the processor does a series of tricks to defeat the player, those who go on to become inviolable, disregard the actions that must be taken to perform certain movements.
Through the video he details these traps and explains how they worked. In terms of inviolability, on certain occasions, when a player attacks, the processor will completely ignore it by initiating its own attack and linking his shot, though the player had started earlier. When you try the same in a two player mode, you can see that the first player's hit connects, canceling the second's attack.
The second trap is related to the so-called "little birds", where the processor always takes 12 frames to respond, ie 1/5 of a second to 60 frames per second, which makes it almost impossible to use this and in the same way impossible to replicate.
Finally, the third trap is associated with special moves, some of which require loading time, such as Guile's Flash Kick. This requires using the player to hold the button, but The computer can run without loading the required time or even marking down, ie standing completely. In the same way in some movements it shortens the frames to connect the attacks immediately.
Here's a video showing you each of the traps that the CPU has.