SPRINGLESS

I was wondering if anyone has ever experienced this.

Today I made some standard white, yeasted,  milk bread, which i do almost every day. Combined the ingredients in the mixer, everything seemed normal. The dough was coming together fine, but I kept testing for a windowpane and I wasn't achieving one that was as strong as normally get. I kept mixing. The windowpane seemed a little bit better but the dough seemed to be getting a bit stickier, which is, from what I understand, a sign of gluten bonds breaking and the dough becoming overmixed. So I stopped mixing and I fermented the dough. It rose fine, practically tripling in size. I divided and shaped, panned, and proofed. In the oven, there was absolutely no oven spring, perhaps even some shrinkage. There was no ripping on the surfaces of the loaves, there were however, on a couple of the loaves, some dents on the tops, as if they had been overproofed, but I know that they weren't. I've heard of little to no ovenspring as well as shrinkage in Ryes and whole wheats, but this was straight white bread flour. Perhaps I missed the ideal kneading point and in fact overkneaded? Why then would it ferment and proof fine? Did I break too many gluten bonds and the dough could'nt hold up to an ovenspring? Anyone?