The prospect of testifying as a witness for the plaintiffs seems to have encouraged Ann Freedman to settle with the de Soles, according to the New York Times:

The case against Ms. Freedman, whose testimony had long been anticipated, is expected to be dismissed in Federal District Court in Manhattan on Monday, said Luke Nikas, a lawyer for Ms. Freedman. But the case against Knoedler, now entering its third week, would continue.

“Ann is pleased to be able to reach this settlement,” said Mr. Nikas. “From the very beginning of these cases, Ann never wanted to keep a penny of the profits she made” from inauthentic works. […]

Mr. Nikas said that he expected Ms. Freedman would still appear as a witness in the case, called by lawyers for the De Soles. He said she would continue to assert that she had believed in the Rosales paintings and would never have sold those works if she had known that they were not genuine.

Knoedler Gallery Director Settles Lawsuit Over Fake Rothko  (The New York Times)