Sounds like it could be a mixing valve issue; if you have one on your water heater. Not totally familiar with the Interstate set up. I’ve had the same issue on my 28’ AS. There are two fixes:
1) Drain the hot water heater. Take off the mixing valve. Make sure the screens are clean. Then soak the mixing valve in white vinegar for at least 2 hours. This will clean off residue that gets on the heat sensors that prevents the mixing valve from opening and mixing hot water with cold water.
2) Get a new mixing valve. You can get them on Amazon.
I did #1 first when I had the problem and it worked. I then proceeded to order another mixing valve as a back up if I didn’t have or couldn’t get white vinegar. I now always carry a spare mixing valve.
You will need a small piper wrench to get the mixing valve off and then tighten it.
By the way, not sure how long you have had your 2017. I have a 2017 28’ and it seems like every year I have some issue with the mixing valve. This is due to sediment in water supplies. I did buy a better water filter as well as a softner. Hopefully that will help some. It is a kind of a pain to go through this every year.