Sound synch issue

[BrettRitchiePhotography]

I have run into a problem today that I have not run into before. I have attempted to synch an audio file from my Rodecaster Pro, with the video file from a recorded video. After using the synch tool in PPro, the middle of the clip is in perfect synch but the start of the audio is lagging behind by about 1 full second. 

I tried stretching the clip to meet the waveform (control and drag) but each time I do, part of the clip disappears miles to the right and I basically have to start all over again. I have tried a dozen times with the same outcome. 

Firstly, does anyone know why the synchronize tool isn't doing it's job (first time it hasn't) and secondly, why is the stretch command cause part of my project to fly off the handle to the right?

Thanks in advance.

[Mike Dziennik]

How quickly does it drift out?

Eg. 1sec out on 10sec clip is different to 1sec on a 1hr clip.

If it's the later, then I would open it in Audition and retime it there for optimal quality and you can target it for dialogue/music etc.

If it's drifting quicker than this then it could be some sort of sampling mismatch with your camera footage.