I know this thread is old BUT it was never solved and I am having the same issues as OP.
I have tried recording the screen with 2 different screen recorders and each time in a random place the audio just cuts out for about a min (the pics are still moving) but sound stops then picks back up after a long time. I have noticed that it does this WHILE recording but does not do this while previewing the slideshow by itself from Power Point.