The double alerts are normal and it can be changed if annoying. By default, your SW subscription within your Settings will alert you to any CC that increases by $x and also by x%. I think the default is $5 and 5%, though I can't recall. Anyway, anytime your CC increases by both $x and x%, then you'll see a double alert. To get rid of the extra going forward, you can go into settings and set either $x or x% to "N" for no and the double aerts will go away.