What was wrong with Lara kissing Harry and not getting burned?
It appears to me most readers who don't like this scene go to Mab's explanation of how True Love Protection can fail and find fault with that. I already wrote my take on Mab's explanation, so there is no point in beating that dead horse.
In finding fault with Mab's explanation, some readers are saying it made far more sense for Lara to get burned when she kissed Harry. I think it was Mira who said, "Lara should have gotten her face burned off." That may be going a bit too far, but in general I don't disagree with those opinions. But there is something else going on this scene that everyone seems to have missed, and this missing element is the real problem. When I put this together, I realized there was an alternative scenario Jim could have written that would have made Mab's tortured explanation of true love protection unnecessary. In fact, it's so obvious to me that maybe Jim considered taking this route but for some reason rejected it and we got what we got. I'll get to that point last.
Ask yourself this question. How did Lara know she wouldn't get burned when she kissed Harry? Before you start coming up with possible explanations, think about the last time you accidentally touched a hot stove or the last time or you touched a casserole dish or any other food container that you took out of a hot over with pot holders, but a few minutes later you accidentally brushed your hand against it and it was still hot enough to raise a blister on your skin. We have all done something like that at sometime in our lives and it is something we try our best to avoid doing and with good reason. Even minor burns are annoyingly painful.
So either Lara would have had one hell of a good reason to accept burning herself or she would had to have known Harry's love protection was gone. The problem is, while I can think of a couple of ways to explain how Lara could have known Harry was no longer protected, in different ways I think each of these explanations are just as unsatisfying as Mab's explanation of why Harry's true love protection broke down.
First, there is no way Lara could physically detect that Harry was no longer protected. We can put that possibility out to pasture. The White Court has had over two thousand years to work on this problem and Lara getting burned by Harry in Peace Talks tells us they haven't figured out a way to do so at this time.
Perhaps Lara could have bargained with someone with enough information to know if Harry was still protected. Of course I'm talking about Mab. There are a couple of problems with this. While Mab appears to know the nuts and bolts of how true love protection works and why it may fail to work, would she have known that Harry was no longer protected? She might have known, but we can't be certain. Even if Mab could have reasoned out that Harry was no longer protected, that is the kind of information Mab doesn't hand out for free. But there is another problem to consider. Even if Lara could offer Mab something in return for this knowledge, even asking about it would be an open admission from Lara that she planned to enslave Mab's knight for her own ends. It is far too obvert a move for Lara to make. That alone should end this line of thought.
OK, perhaps Lara's understanding of how true love protection works told her that Harry was no longer protected. I don't think this explanation works either. First, true love protection is supposed to be rare to begin with. Lara would not only have to know that a person who longer feels worthy of being loved can become vulnerable to the White Court, she would have to know with certainty that this applied to Harry. Knowing that Harry was in grief and suffering from PTSD might be a clue that Harry was vulnerable, but it wouldn't give Lara certainty that she wouldn't get burned if she laid a massive kiss on Harry.
As I suggested above, Jim actually laid the groundwork for an alternative scenario that I think works much better than what we got. It has to do with Lara's blue eyes, which in the past we have only seen described as being grey to silver and once white. Lara told Harry she'd fed extra heavy before their first date. Her hunger being satiated was why it wasn't trying to feed on Harry and Lara didn't get burned when she casually touched Harry with her hands. It made Lara look less dangerous than normal. It didn't have to be that way.
Jim could have given Lara a second reason for giving her demon an extra heavy feeding. Extra feeding for her demon should also give Lara more vampire mojo if she got into a serious fight and needed to heal quickly, without having to immediately feed again. In this scenario Lara's blues eyes don't make her less dangerous, they make her more dangerous.
So when Lara gets annoyed with Harry at her party, when she gives Harry the kiss, he has the same reaction we saw in the book, but this time Lara pulls back in sudden pain as blisters break out on her lips and the skin closest to her lips. Then Lara gets a determined look on her face, the blisters disappear, her eyes are still blue, but a lighter shade of blue than before and Lara kisses Harry a second time and he's powerless to stop her. When Lara again pulls back in pain; maybe she curses, but again she heals herself and her eyes are now dark grey. Harry is all but on his knees at this point. Then Lara tells Harry pretty much the same thing she said in the book, but somewhat modified. Lara tells Harry that she understands he is in pain, that he isn't at the top of his game, but she needs him to focus on the task at hand. Both of them are in danger, and if she needs to do so, Lara can enslave Harry without taking him to bed in order to get him to do his job. Lara gets more energy with sex included, but it isn't necessary when her main goal is just to gain control of someone. Lara tells Harry that just a couple more kisses will do the trick and she could do that right now, but she doesn't want that. Lara tells Harry she doesn't want to offend Winter and she thinks Harry will be more effective "if you can think for yourself."
This way we could have had a more dangerous Lara and avoided Mab's clunky explanation of how true love protection can fail. We know it was going to fail if or when Lara and Harry get married. I don't think much was achieved by having it fail in this book. Plus, the reversal of fortune when Harry unknowingly addicted Lara to Winter would have hit that much harder.