When I can bite people with one of the newer strains (I have Love Sucks/Dry), the button itself is greyed out like they don't want my strain. However, if I do click on the button, the bite seems to go through. It's not super obvious that I can bite them. It don't recall it looking like this when I wear my older strains, like Blistered Hearts or Bindi Bite.

Minor glitch but I thought I would post it anyway.

[EDIT] I was able to infect somebody, so the bites do work, it just doesn't look like could bite them in the first place. I also think it only shows up grey when the other persons signs up for one the strains, as it wasn't greyed out when they selected random (I couldn't bite them anyway, since my strain was immature).