New Flour/ Changed Variables/ Gluten Degradation

Hey Folks,

I'm a self taught (forums and books) baker with a small bakery and pizza joint. I've run into an issue with gluten degradation, and lack the expertise to figure it out. I did some searching and found some posts regarding proteolytic starter...but I also found a lot of other comments and variables.

First, I've had my little bakery for a little over 2 years, and haven't encountered anything resembling this issue in that time period. When I was first selling breads at farmer's markets about 4 years ago I had what may have been the same or similar issue, but I attributed that to the ambient temperature of bulk fermentation (getting into the mid 80F range) being too high..

Things have changed a lot with the Covid19 outbreak. I've been purchasing other flour (generic enriched and bleached all purpose) than the type I was using for the last 2 years. I've been buying that flour for a month or so, with no problem. I recently found a regional supplier of stone ground, organic flour and was excited to purchase some of it.  I used it today for the first time, and the results were terrible. (The flour I was using for the past 2 years was unbleached all purpose.)

General Method: 100% hydration starter left to mature overnight at room temperature (75F). Everything is hand mixed, and my process is a cobbled together mixture of different techniques that HAS been working well...until today.

Mix H20 and levain
Mix Flour and Salt
Incorporate the dry and wet, rest 15 minutes.
Slap and fold a few times until the dough surface gets a little smooth, but before the dough tears. Rest 15 minutes. (This stage 3 times total, with the last rest being 30 minutes)
Stretch and Fold. Rest 30 minutes.

For my dough that I bake the same day, I do 2 stretch and fold intervals 30 minutes apart, then bulk ferment for about 3 hours. For my dough that I bake the next day, I do 3 stretch and fold intervals, oil a tub, and bulk ferment overnight at about 40F.

I followed the same process today, and all of the dough started falling apart about 2 hours into bulk. The only exception was the baguette dough I made that had less levain %. When I left the kitchen, that dough (retarding) still looked strong and "normal."

From what I can tell, the general process hasn't changed, but obviously the ingredients have. I haven't had the problem more than today, but I'm not really very anxious to have it repeatedly.

Can someone with more experience give me some insight? New flour has lower protein %? The added bran/germ from the stone ground whole grain makes the dough THAT much more fragile? Starter % should be adjusted? 

I read about proteolytic starter, but I haven't had any issues until today, and the pizza dough I made with my Neapolitan style pizza flour isn't displaying any of the aforementioned problems.

Help!! And thanks for reading!!!

Chris