We have a fuse and a mini circuit breaker. IIRC, that's what Lippert shows on their wiring diagram. The mini breakers, typically in the A-frame, are very subject to corrosion as you can see in the above pic. The crimp connections on the ring terminals can also be poorly done at the factory. I had one where the wire fell right out when I touched it.
It's a good idea to go through all connections & splices in the A-frame. I ended up putting them all in a PVC watertight box including the circuit breakers.
If your RV was delivered in the winter, it could have been subjected to a lot of salt which the dealers don't rinse off. Our circuit breaker connections were badly corroded withing just a year due to this.
FWIW, you might want to check a few other exterior connections that are also subject to corrosion - the ground to the frame from the converter/panel and the mini circuit breakers for electric stab jacks. We have a breaker attached to the frame for our jacks right next to the motors.