So I was about to benchmark cooling techniques to cool my raspberries when I noticed that my RPI3B Rev 1.2 board was getting abnormally hot out of the box when booting a vanilla Raspbian from the SD card.
Specifically the Broadcom BCM43438 WiFi chip, the micro SD card reader and the SoC was getting hot under 10 seconds of powering the board, out of these 3 the WiFi chip being the hottest, couldnt keep my finger on it after 3 seconds from powering the board with an bootable SD card present.
An interesting thing is that I found that the heating issue only presented itself when the sd card contains a bootable OS. What is interesting that even though there is clearly something wrong with the WiFi chip, the PI boots up fine and I am able to use WiFi to SSH, however out of fear of frying something I shut down the system. DMESG says nothing, except that undervoltage was detected (lol). The polyfuse is normal to the touch.
TLDR: WiFI chip and SD card reader are untouchably hot after 10 seconds of powering up my Pi, what could the cause be, how could I diagnose?