So I'd be on TPU and generalnonsense.net as you can see from screenshots below.
While I have TPU's upload image tab open with my image (while uploading these very same pictures) the clocks increased to 735/1050, but GPU usage remained at 0% and if I closed the tab the clocks resumed once more at 157/300. This seems normal...

So this seems ok and I'm not complaining
BUT:
Then after approximately an hour of normal browsing, GPU usage goes up to 100% and core and vram clocks go up from 157/300 to 735/1010 as if I was gaming.
I noticed because I heard the GPU's fan fluctuating - idling it's at 25% but when this happens it starts going between 27% and 30% making me hear the change in rpm.
This happens even if I don't upload any images, view any gifs, or open any other tabs.
What's even more sinister is that GPU usage remains 100% even after I quit Firefox.
I restart windows, resume FF at the same browsing pages I had left, and GPU usage is once more 0% and the clocks once more at power-saving 157/300.
In fact another weird thing just happened again. While typing out this post GPU usage was 0% and my clocks 157/300. While I was uploading the screenshots GPU usage remained 0% but clocks went up to 735/1010. I closed the screenshot tabs. Clocks went back down to 157/300. After some minutes I checked again but now the GPU clocks somewhat went up again and are now "stuck" at 735/1010 even though all I have been doing was typing this post. :wtf
After like some more minutes to an hour more, my GPU usage will increase to 100%
I tried this out for 5 times now, and the same things always happened.
What's the deal here?