What Blurpee said.
Ashley and Eva are very friendly from their first meeting, hugging, sharing nudes, details about their boyfriends, its a typical best friends relationship.
ORS lesbian pairings are all established early on: Lenca can cuddle with Louise and watch her during sex, she can check out Ivy in their very first scene and the two of them fooled around as teenagers. She adores Hollys book and can masturbate thinking about her etc.
If there were several hints throughout the game that Lena is sexually attracted to Cindy, it would make sense, but there isn't. There isn't a line about jealousy, acknowledging Cindys beauty, worries that Axel claims her because she is attractive etc. Instead her comments and thoughts are ranging from neutrality to annoyance to condescending and spitefulness.
I suppose its possible to rush a developement that late in the game, considering that we also have Ian/Louise and Lena/Wade. But even there there were the occasional line a few chapters before about Ian/Lena acknowledging their attractiveness.
Most pairings are usually proper foreshadowed, which is why they make sense. Lena/Cindy isn't.