[naustin]

Thanks @Pat911, That does seem correct.
Yes, per Dakota Lithium's instructions I charged each battery individually with their included 12V battery then tested that the voltages were within 0.007V of each other before connecting in series then waited 24 hours before connecting Dakota's 48V charger to the cart and ran it until it turned off automatically - which was about 8 minutes. Then the cart ran great for a few days.

When I disconnect the end battery, it measures the same voltage as the others.
I will try your suggestion of connecting them in parallel and charging that way.
Their chargers do turn off automatically when charged (I'm assuming a voltage setpoint).

If this is common for LiFePO4 batteries connected this way, is there a work around when it happens away from home?

FWIW, Dakota Lithium does sell a 48V battery but they advised to use the 4 12V in series for better performance and longevity. I hope this doesn't continue.