Faulty temperature sensors?

Hey guys, concerned 2015 macbook pro owner here. I have the 15" mid 2015 model with the AMD R9 M370X graphics card, 2.8 ghz i7, 16gb ram, 512gb flash storage, and I'm running High Sierra 10.13.1. I recently downloaded HWmonitor just to keep an eye on things, as I am used to monitoring temps on my gaming pc. Call me paranoid but I just feel like I need to know.

For one, the "GPU Die" value is almost always at 35 degrees celsius, it rarely changes (I set the refresh interval to 1 second) and if it does change, it shows 100 or 105 degrees for just 1 second, then it's back to 35 like nothing happened. It was not always like that, it used to read an actual temperature and change its value according to what tasks I was performing. Either way, the fans are still very quiet when it jumps up to 100+, so I am reluctant to believe the reading is accurate.

Even more ridiculous is the "GPU 2 Die" value, which has never moved from a whopping 129 degrees celsius. I mean, that can't be right, considering I turn on my macbook in the morning and bam, already at 129 degrees! Like with the other GPU value, it wasn't always stuck at 129 degrees celsius. None of the other readings HWmonitor shows are strange, it's just the GPU ones.

I performed the hardware test (where you boot up and hold "D"), it turned up nothing.

I don't use my macbook for demanding tasks, the most I ever do is play gameboy games via an emulator, which hardly drives my cpu temps above 50 degrees. I am worried that I'll need to pay for substantial repairs, but then again I have no idea if this is even a hardware issue or merely a glitch in HWmonitor itself. Here's a screenshot.