im thinking it was all over the place before and you just didnt notice it. This behavoir has been going on for a few generations now. Download and install HW monitor and see what you get there and watch what the load is doing . They all bounce by 10C minimum and will bounce more if you have any apps pinging the CPU cores.
I just pulled up Hw monitor on mine for a minute or so just sitting doing nothing but watching it. ckeck out the 20C idle swings. This is also why I never use the CPU as a reference for cooling profiles.
“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein