Brake reservoir leaking...but fluid level is over full.

Very confusing...I see that there is a leak from the brake reservoir, but the brake fluid level is OVER the full mark?

Also, the brake pedal is mushy at first, but stiffens up when I pump it...

Any ideas?

(2011 Nissan Frontier...4WD...6 CYL)

Is it mushy after starting the car? If its mushy after turning off the car this is perfectly normal as some of this is due to residual vacuum built up in the booster. Could be mutually exclusive on the leak and the mushy pedal but had a similar issue with a locked up caliper causing the fluid to rise from the brake fluid boiling over.

This is with the car on...I wouldn't have a reason to hit the brakes with it off...

But one of the rear calipers is locked up...