I suspect that this was to prevent the propane burner from blowing out while driving, although someone that owns this model motorhome may have a better explanation.
In our Bambi, I use a foam filter that goes in a window air conditioner, for this purpose. Otherwise, the burner blows out while traveling, and your refrigerator won't stay cold.
The filter is available from WalMart for about $2.00; and I just position it and close the door on it, trapping it in position. When it gets dirty or starts to deteriorate, I just put another one in. Not necessary when parked. For extended stays, I remove this when setting up camp to improve refrigerator efficiency.