"Wait, what?" Cosima says, probably a little louder than she strictly should in a library. "Back up like... five steps. What do you mean, Kira's stem cells?"

A few months would have been plenty of time for Delphine to change her hair - and worry over Cosima's disappearance could have been enough to wear her down, if nothing else at Dyad did it in the interim.

But it definitely wasn't the same last night if she expects Cosima to take we tried treating you with Kira's stem cells in stride. Cosima is fairly certain she'd remember that. (Did Delphine even know who Kira was? Did she hear it from Dyad?)