I hate computers...I just typed a whole thing..and it didn't post, cause my system freaked out. OH well.....

Check to make sure the oil isn't just from when they bled em. If you clean it off and it comes back then that's an issue, cause if oil is getting out, then air is getting in, and will make the brakes feel mushy and not lock up

Check the bladder to make sure it isn't ripped, twisted, crooked.

Try a new bladder.... check all that and tell us what happens

The brakes do have a break in period though too...so see what happens after you break em in, if it's too cold or you don't have big hills to break em in on fast, then get pulled my a truck and hold the brakes a little...just enough to brake em in. Be carefull thought, ya can over heat em and warp your rotors..ha ha ha