I recently imported a deck from Moxfield, but when I tried to craft the cards in the deck, I noticed more Rare wildcards were required than I was actually missing. I emptied the deck and was notified that I still needed 4 rare wildcards to craft the deck. You can see video of that attached. When I looked at the decklist on Moxfield more closely, I noticed it has a sideboard. Of the 10 cards in that sideboard, I am missing exactly 4 rare cards.

To reproduce this bug, import the deck in SideboardBugList.txt. It contains Ishai, Ojutai Dragonspeaker in the sideboard, which should not be in the average player's collection as it is not obtainable from packs.

Given that brawl decks can be easily differentiated from non-brawl decks when importing due to the presence of a commander, I would suggest one of the two following solutions for decks with a commander and a sideboard.
1. When importing, throw an error message alluding to presence of a sideboard.
2. When importing, simply discard the sideboard and allow the main deck to be imported.

Edit: The Wastes in the main deck seem to cause a separate bug where matchmaking is not possible.