Been having some 20-lap session fun with mixed historic classes (A110, GT40, Cobra Daytona, 330P4, 250 GTO, 906, 908, & 917). Nothing like flying along in a GT40 only to be passed by a 917!
The other poor AI spot is Maison Blanc, where the AI slows down too much. Brake hints may be confusing some AI at Mulsanne, as some of them stop too short and then get rear-ended.
AC's AI, in general, seem to have trouble with high-speed braking into hairpins as they can't tell whether the car ahead has good brakes or poor brakes. Driving the heavy GT40 (poor brakes), I found it useful to not be in the way of an AI with good brakes.