[Mondial]

It looks as if that dogbone style resistor might be a Globar type thermistor. It is designed to run hot and decrease in resistance as in warms up (negative temperature coefficient thermistor). It is probably there to reduce the current surge in the heater string when first turned on. Typically in a series heater string one heater will heat faster than the other and overheat until the rest catch up. The Globar resistor current limits the current until all heaters are up to temperature and then allows full voltage across them. Unless it is obviously bad, I would leave it as is, as it seems to be working properly if the tubes have the proper heater voltages when fully warmed up.