Switching to PCM isn't a fix, it's a workaround that lowers the potential quality of the sound output by the box.
When you could be enjoying proper discrete 5.1 surround sound, you'll just be getting a PCM stereo signal. You could apply Pro-logic processing to it but it's not nearly as good.
BUT - If you don't have the equipment for surround sound - more than two speakers, amp, etc - stick with PCM stereo, will sound no worse.
I notice these tiny drop-outs quite regularly (video stutters occasionally too) but will live with them for now until the box's firmware matures and things like this get fixed. I personally get more enjoyment out of sticking with proper surround sound with the odd glitch than dropping back to 1990's era stereo!
I am in an over subscribed area - Fault ref F003066490