To me, this is the problem. There are some logical issues cleared up the patch, like the timeline of their backstory and early childhood years. But the characters' feelings about their relationships are too unbelievable with the patch.
A woman who has known an 18 year-old almost his entire life and raised him since he was a 3rd grader is going to become flustered over him popping wood in close contact with her, maybe even more than if she were his mother. A step parent, guardian, or an estranged parent might not have the same instinctive repulsion that a full biological, custodial parent would have. If she's his mom, having any sexual thoughts about him are so foreign that she doesn't even recognize them as such. If she's a guardian, then it feels wrong, but possible.