This is concerning my 20 year old son's only credit card. He's a student still living at home, no job. We had him apply for the Discover It card back in 2015. He(we) doesn't use it but occassionaly and pays it off at the statement. He is using it just to use it/keep it active and try to get some credit history started.
Today we looked at his Fico score that they offer. He's at a 772! Which is awesome compared to us - we just hit the 700's lol. But looking at the history it seems that it just went up to 772 after having come down in Oct/Nov from 771 down to 759. At first I thought it was a $38 purchase he had made and then paid off with in a week or so. I couldn't figure out why that would make it drop and was coming here to ask. But then I went and did a little more looking and see that on the same statement that they show him making a payment and the balance going to $0 they upped his limit an extra $500.
Would that be the reason of the score drop of 12 points? It took 6 months for it to go back up. 
I just don't see why something that he has nothing to do with would affect his score like that.
Is there another possibility? He has absolutely nothing else on his credit report so I know it is all connected to this one card.
