May be something as simple as rust forming on the rotors when it sits that long.
Bare steel and moisture and you'll have a micro thin coating of rust. Brake pads will squeal to high heaven for a bit until the rust is worn off.
Can really be seen after a rain storm and then the jeep sits overnight.
Just roll the jeep forward a couple of inches and you'll see a nice shiny spot where the pads were sitting on the rotor, the rest of the rotor will have a dull look to it.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.