I'm amazed no one found the problem - or at least no one left a comment that they did. That makes me feel a little better because I always check the quilt over for problems before I unpin it from the machine, and I was kicking myself for missing it.
Here is the problem block, it's the one with the pink flowers.
Here it is after I fixed it in a photo taken in very different lighting. You can see I left out the crosshatched triangle on the left side of the block.
Blogger is misbehaving, I'm having a terrible time getting the pictures where I want them!