The leaching, should last about two months depending on the weather. When I build a deck from PT wood and in the summer and in Texas, I tell the owners not to stain or seal the deck until it completely dries out. I tell them its like a sponge, its full of chemicals there for can not hold any more. In Texas with 110 plus degrees, the leaching should be done in two months or so. So, if you build a deck in the fall and in a moderate temp area, the leaching could go on until the end of the next summer. Leaching is very slow if at all during moderate and cool months.
Remember, nothing will stick to lumber that is leaching chemicals or sap. if that board is just too full of arsenic and chromate, then just replace the board with another one.
At the lumber yard, you have felt some boards that are heavier than others within the same size. Well those boards are full of stuff and the lighter ones have dried out. The heavy boards are heavy and will leach longer and will really screw up a blade too.
Sorry about the idiot, it is my personal imposter.