What do you mean continued it. The research of submitting buggy patches had ended already (they even had a draft paper). The whole row started because one of the researchers submitted a patches from a (not very good apparently) in progress static analysis tool. The bad quality of the patch led to GKH accusing the submitter that they are continuing. As the article states this was not the case.

Is that the case? I hadn't seen anything conclusive that that actually had happened? (some people said the contacted the IRB, but presumably that was part of what triggered the IRB to look at it)

But looking into this and clearly documenting it is part of what UMN needs to do.

In the most recent email chain where they banned UMN, GKH said that they were going to have to complain to the university again. From what I understand, the IRB review was initiated by the researchers themselves after receiving backlash from the original paper.