is it normal for a FZJ80 front brakes to heat up so quickly in a bumper to bumper traffic?

Unfortunately, yes, it can be normal. It all depends of course on brake pad design, ambient temp outside, your braking habits, gradient of driving surface, etc. If all checks out in your brake system, and there is no mechanical issues, then for sure. Remember, the TLC is a large, heavy vehicle, most quite powerful. It takes a bit of force and friction to get them stopped. If it is bothering you, or become unsafe, look into ceramic brakes and/or performance rotors. Can be pricey, but well worth your piece of mind.