I agree with the others on the excessive mix time. I also think that your salt level, at 3.5%, is much too high. That is about the level of salinity of sea water. You should cut the salt in half. Your yeast level, at about 1.2% IDY, is also too high for a cold fermented dough. I don't know how cold it is this time of year where you live, but the IDY should be closer to about 0.40%.
I might add that your autolyse was not technically an autolyse as conceived by Prof. Raymond Calvel, who was the father of autolyse, because you included the IDY in with the flour and water. With almost 1.2% IDY, you no doubt started to get some fermentation, with acidification of the dough. You can get away with adding some yeast to the dough during the autolyse but it has to be in a very small amount and for a short autolyse rest period so that it doesn't have time to acidify the dough.
If you make all of the suggested changes, I think you should have better results next time.