temperature warning when engine off

Hi all, 2012 has been doing this a few weeks, not very often but sometimes when i'm stopped at a light or something the temperature warning light comes up on the dash, and the very instant i press on the gas and the engine starts the warning disappears. If i start moving under electric power only the light stays on. It might do this for 2 or 3 lights then the warning disappears for a few days.

I have a bluetooth scan tool but not sure what i'm looking for, there's no error codes coming up when i scan. I can bring up a list of temperatures but not sure again what they should be. the main coolant seems normal at around 186-190 when this is happening. I changed the water pump with a new OEM when i changed the head gasket about 6 months ago

the fact the warning disappears instantly when the engine comes on seems important but i'm not sure where to look, any help would be appreaciated