Validators flipping their commision twice in an era and cheating nominators

[florentina57]

Are you asking why a specific validator charging 0% commission receives rewards themselves? If so, each validator in the network receives approximately the same amount of rewards, this is paid from a part of the inflation. These rewards are divided proportionally to the stake on that validator node, if the validator himself has a selfstake then a proportion of the rewards are paid to him, the rest to his other nominators. The commission is just a percentage of the rewards that the validator gets to keep, it can be 0% or 1% or 3% or 5% or even 100% if the validator decides so. Hope this explains it, otherwise, please let me know if I misunderstood your question.