The relay connected to shore power fried on our 2015 Itasca Sunstar due to loose screws on the incoming line. This was a recall by Winnebago, so we had it repaired at the WBG dealer. The entire transfer switch was replaced do to the possibility of the terminal screws getting loose over time/miles. I assume there was a design change on the relay terminal fasteners. We found out about the recall on the Winnie forum.
Checking the terminal screws on a regular basis may have prevent this issue. Just remember to unplug from shore power and make sure the jenny is off before checking the transfer switch. Something I will now do regularly.