Had three instances of this in my game. I attempted to court Jeyne Westerling at the Crag. She seemed interested (relations jumped from 0 to 16). Got permission from her father to visit her, went back to the castle where the option to "attempt to visit a lady" was present but the only option I had was her younger sister, who wasn't at all interested in me (relations dropped from 0 to -2). The same happened with the Yronwood sisters. I also noticed this with lords I recruited into my own house after completing the Qarthagar quest. My lords without fiefs were offering up their daughters to me, (I think there were 4 at my castle) but it would only allow me to visit with one of them. The problem is once you court a lady the only way to access them again seems to be through the "attempt to visit a lady" option so effectively they are inaccessible. Not really an issue as there are lots of options, but was quite frustrating at first.
I've had this issue too. With Sansa and Arya Stark. Hopefully it gets fixed soon.
same issue with the sand ladies in the south