What I find unusual is you cut all pieces for your block with the same template and two of the tri-rec units came out perfect and two did not. Additionally the two that are perfect are exactly opposite of each other as are the two that are not. Usually when sewing this block together you are sewing the two opposite sides first, like top and bottom, then the other two sides.
Are the two sides that are off the sides you attached first or second? I am thinking your problem is not with the template cutting but somehow something is different when you are attaching the two sides that are off.
When you make your tri-rec units do they all measure exactly the same before assembling into the star block? When you look at your completed tri rec unit do you have the normal 1/4" seam allowance from the top of the point to the raw edge of the unit?
If the answer to both of those question is yes, then that means the problem is when you sew the tri rec unit to your square in a square unit.