Glad you got it fixed.
I had a similar odd issue with my 07 once about 2 yrs ago.
Original batteries, wife said it felt like batteries were bad, started hard that day. I went out and it acted like half dead batteries. Barely cranked, no fire.
I figured the batts just gave up. Hooked jumper cables to it and it fired immediately and easily. Disconnected jumpers right away. Started it about 10 times in a row with no issue and never had another issue. Think the Rams are finicky to any corrosion or connection problems. Never did pinpoint what it was.