Don’t see your model, mine series 3. It has a 1650 watt element.
Most likely you are plugged into a receptacle on a 15 amp circuit. So without tripping breaker, to get full power it needs 110 volts at the unit. (P=EI, 1650=110x15)
It is not uncommon to see voltage AT THE SERVICE ENTRANCE that low occasionally or even frequently. You get voltage drops every step on the way to the smoker.
A house 15 amp circuit likely is wired with 14 gauge. You lose about 8 volts for every 100 feet of wire, so would like to plug in as close to breaker panel as possible.
Would like to plug the smoker cord directly into the receptacle, not always possible.
So Will want the heaviest and the shortest extension cord possible.
For every 100 feet, you lose about 12 volts over a 16ga, 8 volts over a 14ga, and 5 volts over a 12 ga.
It’s easy to see how it is common for people to be ‘starving’ their heating element, and failing to achieve maximum temperatures.