Welcome and Hafa Adai from Guam!
Pieces that small, I wouldn't put in the washer.
If you want to wash them, I'd put them for a "soak" in a dishpan, then rinse very well.
But, if it were me, I WOULD NOT wash them.
Your blocks could be off because your seams are not a "true" 1/4 inch. You could have ironed them wrong, meaning that instead of the seam being flat, there is a bit of a "ridge" in it. Kinda hard to explain it.
You could use some starch on them. Just give them a spray and iron them down, would give them a bit of body to make them sew better. If the piece is too wet from the starch, just let it dry, then iron.