I know I've asked you this before, but I can't recall the answer. Is this your second chart?
TCOYF suggests excluding temps that don't follow the rule of thumb. They suggest when the temps might be artificially high due to fever, restless, alcohol etc.
This doesn't seem to be your situation. The book also says that the preovulatory phase can vary considerably both between women and within any one woman's pattern from cycle to cycle. I've dropped a few on my charts before.
Also, do you get the same exact number of hours of sleep each night? That may affect things. Stress can affect it as well.
Unless you see some type of pattern, I would try not to worry. For example, if you had really high temps in the pre-o phase, yet the cycle turned out to be anovulatory then there could possibly be a connection. But, how many charts would you need to prove that pattern? KWIM? Most doctors would probably brush it off as a coincidence. They like b/w and u/s's.
I've analyzed my charts over and over. (not lately) I was able to predict when a cycle might be ano, but temps alone didn't help me. Also, it wasn't hard to do if I only ovulated 50% of the time on my medicated clomid cycles.
The more charts one has the more patterns one can possibly find. Is there a medical explanation for every pattern?

For some, I'd say yes for example a very short lp.