The superko rule is indeed simple in theory, but in practice it can be hard to verify a violation (i.e. detecting a long cycle in your IRL games, such as Cycle at Sensei's Library, especially when both players make an effort What do you think Shin Jinseo and Katago's ranks would be on OGS? - #8 by gennan).
Edit: OP’s question is a similar case as the example under 3-move cycles on that senseis page.