Brakes sound very weird. If there's fluid leaving the system back into the res constantly then something must be taking its place, and that'd most likely be air which would suggest either an ineffective bleed or a leak elsewhere.
If you've checked over lines/connections and they all seem ok (I'd expect the fluid to leave entirely if this was the case, usually) then perhaps try rebleeding - EziBleed/other pressure bleeder is the way to go, but you will want to actuate the pedal as part of the process and don't forget to bleed the master cylinder last too. It's possible to bleed the ABS system though I think you need VCDS.