NO. I don't know where that one poster got his LOOP from, but there is no problem
IN fact those who have Solar, in addiotion to a converter and/or Inverter/charger Well.
I run both a coverter and inverter/charger (once I get it fixed,, Old age issue, ) in parallel, along with the engine alternator.. With DC systems you can have multiple "Sources" in parallel. as many as you want.. The only "Danger" is that the one with the highest voltage at the moment may do most all the work while the others sit there
Thus when on shore power at night the converter (or inverter/charger) will keep the batteries charged but if SHORE POWER is lost the batteries SUPPLY power till the sun comes up then the SOLAR charges.
IN the day both Solar and Shore may charge depending on the voltage settings.. Or one may shut down under the controller when it "Sees" the other. In either case NO damage happens.
Think of 5 people all pushing on the same stuck car.> They all work together
You might want to stop reading this post now...
But in an AC system they PUsh/pull/push/pull and if say 2 are pushing when 3 are pulling.. Well that don't work well.