Thiols? Or something else?

So I think I've got the problem identified, but I'm not entirely certain and would like confirmation.

Last week I noticed my dough going slack after fermentation when I was making a pizza dough. This was no real problem for the pizza dough since I was going for something that was spread out, but I knew it wouldn't be good for bread. Just to make absolutely certain this was a recurring problem, I cranked out a few small loaves of bread over the next couple days. All of them had the same problem: the dough would be fine going into the pre-ferment, but when it came out it would have a very loose consistency. This consistency would improve somewhat when I added more flour for the final dough, but it would lose shape again over the course of rising. It seemed like the more I kneaded the dough the quicker it started disintegrating into a goopy mess that stuck to everything.

I've never had this problem before. Reading threads here, I think it might be an abundance of thiol compounds due to the fact that I switched from Gold Medal AP flour to KA Bread Flour when mixing the starter about three weeks ago since I had run out of AP flour and had a large surplus of bread flour. I also started keeping my starter a bit more moist a little before that switch, from 1/3/5 to 1/3/3 s/w/f. The problem (and why I'm doubting this and thus posting here) is that they're both white flours, not whole grain flours, and I only saw this problem cited when the baker had switched from whole wheat to white.

Is this increased activity from those bacteria that produce thiol compounds, or is it something else that I am missing?