Thermal protection switch replacement in recessed incandescent can lights
Yes it has always been possible to replace a 60 with a 100 in one of these fixtures but that would set off the thermal even faster. Back in the day before thermal cutouts were installed people started fires by using an oversized lamp in a fixture that was not protected. If you cover it with insulation it holds the heat and only exacerbates the problem. 

Replace the incandescent with the LED and hopefully the cooler lamp will keep it from tripping the aging thermal relay. 

If it still trips you may have to remove the thermal and replace it or replace the whole fixture. 

Good luck!