I cannot reproduce this bug, but did find something related where using a condom would prevent Felicia from impregnating you anally. That bug will be fixed next patch
Ahhhh... yeah. Similar issues to the condoms really (it was checking the genitals selected for the scene if they blocked pregnancy checks, regardless if they were the relevant genitals, as this is the only scene that involves multiple player orifices currently), hadn't thought about that. The fix I used for the condoms should work for the strap-on issue too. It will probably go live somewhere after Christmas.