After much experimentation and observation, all I can say is the problem of single grass blade inexplicably left uncut has got to be directly related to attempting to mulch grass that has grown too long. That doesn't do much to explain how one blade of grass can avoid the cut when all the adjacent blades are chopped down to size, but the mowing results are better when mowing earlier rather then later. I do have to say my lawn is a little bumpy. I have not observed that as being a cause.
And, since I don't mind mowing, but have better things to do with my time, what I do now when the grass is too long and I want a clean cut, is to mow the long grass in bag mode with no bag. The clippings are nicely expelled out of the back. Then, I switch it back to mulch mode and go over the noticeable clippings again, and they mulch up pretty well. I'm not left with hay on the lawn.
Best mowing to all my fellow Honda owners, and......Bonsai!!!!