You might check all your Speedbleeders and make sure they are not leaking.
After switching to speedbleeders all was fine until my son found one of the rubber caps in the driveway. I thought "Uh Oh!".
Sure enough one of the bleeders had a very small leak. I had it replaced but the threads in the caliper were just slightly sloppy. I used some teflon thread tape and that snugged them up just enough and no more leaks.