With sugary things, it can really be dependent on a lot of things. For instance, I do a pulled pork and cover the pork in non-diet root beer made with cane sugar. Never had a problem. But, once I shred it and cover it in BBQ sauce, there is a limit to how long I can let it cook before it will crisp the sugar around the edges. The time also depends on which one of my pots I use (size) and which heat setting. There are just so many variables and I think sometimes that recipes just need tweaking. For me, skip thick sugary sauces for long cooks in the pots and only use them long enough to add flavor and make them warm.
So when do you think I should add the sauce?