Sean,
This deep into a training block PE is always higher. HR is usually lower – depressed by fatigue. So the fact you are getting your heart rate up tells me you are doing well. As you reach both peak fatigue and peak fitness heart rate responses change. You will see them change again in your taper as you dump the fatigue part. These changes can be unsettling.
I recommend making a slight change to your training plan. This (week 10) Sunday ride for 3 hours instead of 6 hours. Some athletes do better on a 3 week taper for a PR solo 24 (me) and some a 2 week taper. You sound like you are ready for the 3 week taper. The only real difference between is the length of the Sunday ride.
See you at OP. I'm racing duo this time around. It is one of my fav solo courses. I'll be getting there late Thur night and staying at the race site all weekend. We have a 20 x 10 party tent set up somewhere between the rock drop and timing tent (hopefully). Come and say Hi.
Shoot over if any more questions about training or the OP course/race site come up.
Lynda