I would suggest that you inspect all the connections to the mini-breakers and also inside the 4x4" junction box. The factory can sometimes do a pretty bad job of wiring in the A-frame area.
The first photo shows what our 2 breakers looked like in just 2 years - a corroded mess. If that wasn't bad enough, the #10 positive wire on the downstream of the breaker heading into the junction box just fell out of the ring terminal due to a bad crimp job at the factory - see 2nd photo. The ground lug was badly corroded and one of the #10 wires had less than 1/2 the strands under the screw - 3rd photo. Just yesterday I finished installing a water-tight PVC junction box to replace the original leaky indoor-rated metal box. I installed new standard mini-breakers inside it and relocated all splices & connection inside it - shown in last photo.
The marine rated breakers look a good idea. 100 percent better than how the factory does it.