I had the same problem. I have the black exhaust pipes, haven't heard anyone with the chrome pipes having that problem. with the cats being so close I thought that might be the reason for the high heat. took the cats out , hasn't been any worse but still have melted turn signal lights.
Part of the inner wall of the drivers footwell on mine look like that ,there is a small plastic bulge ( part of the design ) that comes close to the gearbox has melted similar. Very localized and not really a concern , other than its right next to the gearbox which I would have thought would be fairly cool ?
I've also discovered one of my turn signals melted. I was thinking about installing a heat shield like the one at the link below. Has anybody done something like this? Any thoughts about it?
I fitted Harley heat shields over the headers - they are slightly curved so run to a point just under the pipes. Mine are also holed which matches the main silencer heat shields. Just fitted additional Morgan Supersports logo heat shields to the front pipes as well.