Co2 pressure problem?

Hello I got my Co2 an keg hook up to carbonate my beer. So here my worry I have my regulator is set to 30psi but I notice after a little bit it goes from 30psi down to something like 25psi now what would cause this issue?

These psi gauges are not always that great and they aren’t super responsive. Just keep in mind that your lungs can force out about 2 psi, so your gauge is only off you blowing as hard as you can against someone else’s mouth doing the same thing. Hope that image helps.

Did find out. Forces of nature. Once you set your gauge to. 25 psi forced carbonation. You shake the keg. Every few min. You pressure drops. And got to reset your gauge. Few times