Has anyone documented a "hot" can of powder. By hot I mean faster burn rate making the load shoot higher? I was shooting today and had my rifle pretty well dialed in at 50, 100, and was almost gold on 150 when I ran out of powder. I opened a new can and my bullets immediately started hitting 8" higher at 150 yards. I confirmed this at 100 yards it was now hitting higher.
My flask and quick loads have been in a cool dry area since October. They were under my reloading bench in my house next to the computer I am on right now. There are only two things I can think of.

#1- moisture- I know that there has been no water or any other fluids in the area. The moisture in the air would be the same as the rest of the house. This powder was not in a air tight container.

#2- Hot can of powder- The outside temp is in the 50's and all the powder was in shade as I was shooting. This can was sealed and was in a air tight container.

I am a little confused at this to be honest. I have never documented a change like this to this extent. I didn't have another rifle with me that was sighted in to test both powders but the rifle I was using was super close. I had to lower the sights by a lot on the new powder. I was using a Williams FP peep and I had to lower the sights by two marks on the scale. It was right at 42 "clicks" that seems like a lot of rise in elevation to me.
Both powders were Pyrodex P. I don't have the production code on the older powder dang the luck.