Fuel Pressure with key out of ignition

I have a FP gauge installed on the fuel rail and noticed the FP went down to zero when I shut the car off (no surprise), but almost immediately it crept all the way up to 30.5 psi with the car off and the key out of the ignition. after about five mins it slowly began to creep back down. Is this normal? I was adjusting my FP prior to this an wondered if maybe this had anything to do with this.

i would say that it is the excess pressure still in the lines that does that. Then as it bleeds back to the tank it slowly decreases. I may be wrong, and if i am some of the seasoned SC guys will let you know. But that's just my thought on it.