To me part of being a friend is giving them the benefit of the doubt. It seems that this might be the case, I'd assume that she had a valid reason and that that is enough. I'd mention it but not make a huge deal from it.

I also got married and divorced I didn't ask my best friend to my wedding because I knew that it would cost him a lot of cash he didn't have, to get there. If I asked him to go, he would have been there somehow and been broke afterwards. He understood, and was upset that he was not there, he also accused me of waiting until after he paid his rent for the month on purpose. I did and he new it, I know he has my back just as I have his even if he doesn't like it.