Yes it does mask issues because why isnt the car cooling correctly that you have to have the fans come on early when the system was not designed to. Thats why anytime you turn on A/C they come on and from 105-110 they come on because the viscous fan and normal driving it should never get that hot overall. That is an issue if it does. The resistor masks the problem.

problem 1 is usually thermnostat staying open too long letting system throughout get hot.

problem 2 is viscous fan not staying engaged at high heat because its leaked out all its internal oil

problem 3 is low freon charge (normally due to evap leak) or a bad sensor on the dryer, or the ballast on the fenerwell that supplies power to the electric fans.

problem 4 can be the water pump.

problem 5 reservoir cap has a leak which allows boiling in the system.

problem 6 is scale buildup in the radiator tubes not allowing proper cooling, also bent fins, leaves whatever the case may be.

I hope you find the issue but it is an issue if you let it go if its getting close to 120(redline).

I replaced most of my stuff over 3 years and now with everything cleaned, new and working I never go past 100 with A/C on full blast stopped or driving. I normally set at 85 all the time with A/C on cool days just under 90 on hot days driving to Spokane, Wa when its hot.