JLSeagul,
Yes you'r right if the liquid is near the flash point it may flash.
I have had trouble with liquid Chlorine well below the flash point flashing in both Coreolis and Vortex meters.
I put it down to the additional mechanical energy imparted bu the vibrating tube or vortexing.
Roy
In my youth I observed circular chart orifice meters on steam condensate. Instead of the pen drawing a line, the chart looked like it was air brushed. I suspected that this was noise from the condensate flashing across the plate.