There's a _possibility_ that it was just that suddenly after the failed come-on, her commits suddenly needed a lot of reverting (though you'd think Github, of all companies, would have decent policies on communicating on changes; silent reversion is not normal and is likely to cause a lot of confusion).
However, it allegedly started happening _after_ the failed come-on, which would make it retaliatory. That's unprofessional, and probably amounts to gross misconduct.
> "However, it allegedly started happening _after_ the failed come-on, which would make it retaliatory."
That would make it possibly retaliatory. It remains possible (although I would not say that I consider it likely) that there were legitimate technical justifications for reverts made after the rejection, and that the sequencing of those two events was entirely coincidental.
If I were management at github, I would grill the employee who reverted those changes for a technical justification for the reverts. If the justification seemed tenuous or strained, I would fire them on the spot. I would however make sure to grill them before firing them, as it is not certain that there was no legitimate technical justification.
However, it allegedly started happening _after_ the failed come-on, which would make it retaliatory. That's unprofessional, and probably amounts to gross misconduct.