DURING CLBOUT FROM DCA; FMGC SOFTWARE PROB CAUSED ERRONEOUS FLT DIRECTOR INFO WHICH; BEING USED BY THE PF; CAPT; TOOK THE ACFT CLOSE TO THE PROHIBITED AREA. DEP CTLR INTERVENED AND TURNED ACFT. FO HAD CORRECT RAW DATA ON HIS INSTS.

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A-320 GLASS COCKPIT. LOADED FMGC CORRECTLY (BY CAPT) AND VERIFIED BY SELF (FO). ADDED POINT/BEARING/DISTANCE OF DCA 328/50 TO COMPLY WITH DEP. CAPT FLYING UTILIZING MANAGED NAV AND USING FLT DIRECTOR FOR GUIDANCE. I HAD DCA 328 DEG HARD TUNED AND DISPLAYED ON MY SIDE ON RAD NAV PAGE. (CEILING WAS APPROX 1200-1500 OVCST.) AFTER ROTATION; CAPT CALLED FOR GEAR UP AND BEGAN FLYING FLT DIRECTOR. I NOTICED 328 DEG RADIAL HAD ALREADY BEEN PASSED ON MY RAW DATA ROSE VOR CDI. I TOLD HIM TO TURN L TO INTERCEPT; BUT HIS FMGC WAS STILL SHOWING RADIAL AT OUR 12 O'CLOCK AND APPROX 2 MI. I BEGAN TO TELL CAPT TO TURN AGAIN WHEN ATC RADIOED A TURN TO US. APPROX 30 SECONDS LATER WE WERE GIVEN A PHONE NUMBER TO CALL. IRONICALLY; AT OUR DEST WAS AN AIRBUS TECHNICIAN (WHO JUST HAPPENED TO BE CHKING SOME INFO ON THE NEXT AFT WE WERE TO FLY). HE INFORMED US THAT IT IS A SOFTWARE PROB THEY (AIRBUS) ARE AWARE OF. THE FMGC LAGS IN MANY INSTANCES SUCH AS THE ONE WE ENCOUNTERED. WE ARE GOING TO RECOMMEND TO OUR COMPANY ALL DEPS FROM DCA WITHOUT GOOD VISIBILITY SHOULD HARD TUNE AND FLY RAW DATA -- NOT RELY ON FMGC INFO.