Which firmware are you using? Check Setup > Device Setup > Firmware Information for the Main firmware version.
I suggest you update to the Public Beta firmware released last night. It's Main version number will end 0719B. Download it from the OPPO web site for installation via USB stick:
NOTE: You must do a Reset Factory Defaults after installing this. A chance will be offered on the first power up after the install.
With that firmware, audio and video are correctly in sync at the player's outputs for Blu-ray playback. So if you are still seeing a sync error, it's time to start looking for causes external to the player. Report back and we'll have some suggestions for you.