Actually yes, from looking at their CVs, these two never worked at the same school in the same department at the same time. Cornell left the Penn DEPARTMENT OF LAW the year that Warren started there and as it began turning into an actual LAW SCHOOL. I'm going to assume that transition had far more to do with the changes than anything Warren, a lowly single professor in her first true full professorship, did "henchwoman" or not.
Cornell was there 1983-1987, Warren moved from the U of Texas School of Law in 1987 and was at Penn 1987-1995 when she went to Harvard.
Derrick Bell began his protest in 1986 and resigned in 1991.