I think the timing is entirely coincidental. The agenda would have been set before Saturday afternoon. With the Legislature considering the impeachment of Hall, having given clear directions not to take any employment action with respect to Powers and with Powers about to testify in the Legislature investigation in just a few days, it would be more than stupid for any Regent to give the Legislature the finger and move against Powers.
Plus, with the Legislature moving to protect the academic integrity of UT against Rick Perry's "reforms" the Regents would be laughingstocks if they fired the sitting Chair of the AAU because he refused to fire a head football coach. Doing so would tarnish the academic reputation of UT among other AAU schools beyond repair.