Fuel pressure rising at idle?

I've got a nexus fuel pressure gauge in my Bullitt (electric), normally reads 30psi at idle. The gauges have been in the car for half a year with no problems.

For the past week it has been rising at idle to 50psi gradually, RPM is constant and doesn't change. The pressure goes down after a long highway run. The car is usually hot (at operating temp) when the pressure is rising.

Also had CEL "Mass Evap leak detected" set, cleared last week, it has not set again.

Bad sender on the gauge or something else?

Thanks for the info. I've been told that the "Mass Evap leak detected" is related to a vaccum leak (most likely gas cap). It was pretty strange that the CEL came on because the car was running great. I was wondering if anything had changed and then I started to see the Fuel pressure gauge go red (warning me of something).

Good to know it's all normal, it's been extremely hot these past two weeks here so it all adds up.

Thanks again.