Overproofed? 2nd Porridge Loaf Disaster

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Two weeks ago I tried to make an oatmeal porridge loaf and it turned into soup. I tried again today and I thought it was going really well, but when I tried to pre-shape after a 4-hour bulk at 82 degrees (significant mixing followed by 4 sets of stretch and fold), the dough was extremely stringy (more like starter than dough) and I found it impossible to shape.

While it wasn't liquid like my last attempt, I just couldn't do a normal shaping job as it stuck to everything. I did my best to get it somewhat round and just placed it in a bowl and into the fridge. I then tried shaping again after a few hours and it was much easier with the cold dough. There wasn't much oven spring and the crumb was super dense and wet. I am assuming this is because I broke the gluten strands or they were destroyed from over proofing. I only did bulk for 4 hours at 81 or so degrees, but do oats and honey really speed up the fermentation process? It had only expanded about 35% so I thought it was well proofed. Do you think it was over proofed + a bit too much liquid? 

This recipe I used:

200g starter (100%)

190g multi-grain porridge

377g water in the soaker

414g water in final dough

800g flour (20% whole wheat and 80% bread)

22g salt

55g honey

20g yogurt 

Is the hydration meant to be at 85% or am I misreading?  Perhaps cut your hydration back to something lower.

377 water + 414 water + 55 honey + 20 yogurt = 866

190 porridge (I assume this is just dry flakes?) + 800 flour + 22 salt = 1012

This will be 85% hydration, unless I misunderstand something.

There wasn't much oven spring and it felt like the gluten had started to deteriorate when I tried to shape the dough. Do you think the honey and oat soaker would cause really quick fermentation? I am surprised it could get so overproofed in just 4 hours. The dough had only expanded by 35% or so.