i have the same problem all ports show short cicuit and i changed allreday the powerbox and the problem contiunes, voltage is above 24volts with the proper conctor , i use FW 6.48.3 also tried the newest beta with no results
any other option what that could be ? (mine is not a PRO )

i have this "bug" too and if i put one poe with the priority 11, i get the overload only on that port, even though that port doesnt pull any power! so for me its a bug, and sill not fixed with firmare 6.48.3