Your local Dunlop dealer is a bastard (with too many nails).
What pressure are you running?
I would think 36 would be fine; I run mine at 38 and don’t get any issues. 40 would conceivably produce that on a warm day doing hwy km’s. You have good/reliable pressure gauge?
Be interesting to hear what Pirelli says. In the old days, there would be a tyre reseller who knows it all and could easily diagnose.
Neale, I've been a long long time Avon tyres user. when I started riding HD's Dunlop were not common on HD's, GoodYear was what they came with new. so I had never used Dunlop. then was using Bridgstone battle axe on my Buell needed a new tyre, local bike tyre guy only used Dunny's, so got one on rear. less than 1,000 got a flat ( this was tubeless. I'm back on Avon on both my bikes. Bridgstone's good, never had flats with them. by the way was wood that went into my dunny's and did not seal the tubeless, so it went flat on the road, in the bush.