First of all, these blocks are beautiful. I agree that the slight mismatch is not noticable and as far as I'm concerned doesn't detract from the beauty at all.
But I also know that when this kind of thing bothers me, I just have to figure it out.
I have actually resorted to working from both ends of the seam until I get close enough to make sure the intersection matches. After pinning I use a basting stitch and sew a little way in from both ends then when I make sure I have a match it is easy to remove those basting stitches. I don't use this very often but if something is making me crazy I will resort to crazy ways to make it work. lol
You are working on the bias so there is always a risk of stretching. I find that to be a real issue in blocks like the ones you are working on.
Good luck. They are beautiful.