Are your batteries from Mil Supply really new?
Batteries received from the military supply system may have sat in a warehouse for up to a couple of years. And, because most warehouses are not climate controlled, warm temperatures increase the rate of self-discharge. While pure lead/tin batteries can be stored this long, it doesn’t mean they are ready to use. So, even though they are in the box and seem brand new, there’s a good chance they need some maintenance prior to installation.