Freightliner Cascadia Loses Prime every so often

I got a 2017 freightliner Cascadia dd13. This truck would lose prime like once a month and fuel drain back in tank. I was wondering if the 2 stage valve is getting stuck open. I have already replaced the water separator check valve. The truck would run shut it off and then it wouldn't start back up. The fuel hand primmer wont prime it up no more. Just have to dump fuel in water separator and prime with Detroit tool to get it to prime. I do not run no aftermarket filters all oem. Just curious if you guys have dealt with this before. Thanks