Quoted from paul_8788:Wonder what the differences are with the boards.
The difference is your board's parts are borderline faulty and go in and out of spec. You're obviously welcome to live with it, but could it negatively affect other components downstream? It's affecting relays. Are those relays a protection circuit?
I mean, only the entire pin is dependent on stable power to perform properly and if you're experiencing the equivalent of little "brown outs" due to unstable power which is clearly tripping relays, so if it were me, I wouldn't ignore that for very long. Components aren't self healing, it's just more likely going to degrade and get worse over time. Could other components suffer by waiting and allowing this to continue?