I carefully calculated the heat levels and saw that I got 0 heat transfer (not even 1) from multiple grunt hits. Which Kyzrati explained:
half the time there is zero heat generated
No wonder I didn't feel anything.
Cogmind receives only 6/9/12 heat from low/medium/high heat transfer per shot.
Note that shields (including Hardlight Generators) decrease received heat transfer.
I believe that Thermal Converters output energy based on the listed values of heat transfer, rather than actual ones. (that time I used it, I did feel bonus energy)
So this is what makes Heat Shieldings useless.
It's also good to know that melting immune robots receive less heat transfer. I was wondering why MC's heat levels were not rising despite him using no cooling devices, a bunch of hot armor and a bunch of firemen hiting him. (melting immune robots still lose evasion and accuracy with high temperatures)