I noticed the following on the boards that are likely misprints:
2B: Lower left green conveyer points off the board instead of on like all the others. Possibly this is intended, or possibly all the green arrows should have point in (having the different speed conveyers would then have a point at least).
4A: The lower right blue corner conveyer points in the wrong direction. This is a doozy for people with spatial orientation issues.
Are your sure the 3 like ones are pointing on the board? On my 2B, all of the green conveyors point off the board, except the lower left, which points onto the board.
Also, on 2A, 3 of the conveyors have length 6, while the one on the right side of the board has only 5. If looks like the last conveyor square is missing, assuming they are all meant to be symmetrical.