Yeah, Im curious as well. Might be worth a shot at just replacing the gasket and try for what its worth. Maybe after heat expansion a little bit of a vacuum leak. Unlikely, but....
It is minor, but drives me nuts because it shouldnt do that. And I cant explain why it happens. Its perfectly fine for a while, until driving around for a little bit.
What idle issues are being reported with PRL? Ive had no persay idle issues, but after driving for a while the idle tends to stay up a tad longer than it should.
We do get a decent winter here. However, the Type R is parked for the winter as soon as salt/brine is on the ground. Havent driven it below 8 degrees (46 Fahrenheit).