Wood defects and how they come to be

Ever since I bought my sawmill I've been studying how to best dry wood without a kiln, this is obviously to maximize how much of the wood is marketable and minimize how much ends up as firewood.  I'm OK but not great and since I haven't the ability nor the desire to complete with folks who have faster mills, a kiln and all the material handling equipment that can make the price of a mill into a rounding error that few consider before diving into milling, I stick with high margin woods.  For me and given what's locally available, that's cherry, walnut, maple sometimes cedar and white oak.  This isn't about any of that though, this is about some 40+ year old PT southern yellow pine.  Given the age, I'm certain it was CCA and not ACQ treated though that may or may not make a difference.  This is your basic 2×6 from 1980 that's been a deck board all it's life along with those pictured adjacent.  This board has been oozing sap since installation and I suspect, though I'm not certain, it's been cleaned off before.  This board has pumped out nearly a half pint of sap that congealed to an extremely high viscosity feeling almost like cured silicone caulk.  It's the only one of 81 boards that has exhibited this behavior.