Some of it turns on distinctions that don't make all that much difference: Sessions suggested that she was more involved in the litigation activities of the Puerto Rican fund than she had said she was (and she denied ever denying that she wasn't involved, if you can follow that).
But Sotomayor, who was a board member of the committee, may or may not have reviewed particular documents, but those who worked with her at the time, more than 20 years ago, told the Los Angeles Times when she was nominated that Sotomayor was sympathetic to the fund's mission. And Sotomayor herself hasn't said that she wasn't. Her association with the fund is clear. What isn't is whether that makes any difference now with regard to her judicial approach.
PRLDF is the Puerto Rican version of the ALCU. Their goal is to reinterpret our laws to benefit Puerto Ricans. One of the issues that I recall is that the PRLDF filed a complaint about Mayor Dinkens for referring to the FALN as terrorists. The PRLDF claimed that Dinkens was insensitive and that he risked offending Puerto Ricans who thought of the FALN as a legitimate protest group.