"Cold spot" on my heated bed?

[old man emu]

Here is a photo of my printer:
Lights Off - flashlit.jpg

I have a Magma hot end and the recommendation is to run a fan with it.

OME

[gmay3]

OME, I also have an all metal hotend (hexagon) that has a recommendation to run the fan at all times. Not running the fan accidently caused my printer to fail after 30 mins of printing ABS. The problem is that without the fan, it heats up the aluminum mounting plate that holds the hot end in place, and the ABS extruder parts begin to melt which caused a really bad jam for me.