Blinking Binding

I'm not sure how many quilts I've made over the years, but there are quite a few, and the vast majority have been finished with continuous non-bias binding.  That must be a fair amount of binding.   I understand how to do it, I use it regularly, I teach other people how to do it . . .

So why did I stitch such a huge seam allowance this time?  Now the binding won't fold to the back of the quilt - not until I've spent hours and hours unsewing, and then stitched it again nearer the edge.

"Fiddlesticks", and other words!