Future reference:
You can try to "block" some blocks by spritzing them with water (or a little starch) slightly tuggin them into the correct shape and pinning them to dry. That has worked for me on some blocks.
Another method is to add sashing to all blocks and adjust the sashing so the blocks are all the same size. It looks like the BOM blocks are framed.
A third method - if the difference isn't that glaring, adjust the seam allowance when sewing the blocks together, particularly when there are points.
Lastly - and YES, I have done this: Undo the block and resew it with a scant 1/4".