OK, so with over-voltage with the new vehicles (is the OP's that new?) and the battery red dash light comes on from the solar's voltage being over spec, does the alternator shut down or not?
If it does,, will it come back on by itself if the voltage is reduced to within spec (by adding load maybe)
Are there model years where it won't matter like my 1991, but it does matter starting about ? year, where the alternator does shut down, but then later years than that ? year, the alternator stays on and just the light stays on too?
If so, then members will know what to do depending on what year their RVs are.
I had that engine stumble reported earlier, but that 2016 van is a Fiat, made in Turkey with parts from everywhere, so not sure it is typical.