Audio Sync and "Lag" Issues

Has anyone encountered audio where the audio continues to "fall behind" as the clip goes on? This is driving me crazy!

CONTEXT:

• I'm recording A Roll (talking head) using a camera and Rode VideoMic (no issues there obviously)
• I'm also recording screen capture on the laptop (I do tutorial videos) and Im recording video through my webcam (I don't use this audio in the final video, only for syncing purposes)
• I clap 3 times at the beginning so I can sync the audio BUT

The screen capture audio somehow keeps LAGGING BEHIND as the time goes on. So let's say the 2 audio tracks are perfectly in sync at the beginning, then the screen capture audio falls behind by 10 frames 20 minutes in, then 20 frames 30 minutes in, then 30 frames 40 minutes in...

Is this a common problem? 

It shouldn't be, but it depends in the specifications of the various media. The camera, Rode, screen capture, frame rates and audio sample rates. Also the devices being used might help. Some devices just don't do sync. 

What you describe is a textbook sample rate issue.  Your two videos are recording audio at different sample rates.  Audio sample rates in video should always be 48kHz.

It is a audio sample rate problem but I think it has to to with the screen rec software not using a constant (or stable) audio clock. I think it It doesn’t matter what the sample rate is it just has to be stable/constant. Have you tried using a diff screen rec software? I dont do screen rec so can’t recommend any.