I had the same thing happen to me today while streaming from an online source.
My preferred output is 320kb, stereo, include CRC. No system sounds.
It's intermittent and only noticeable on playback.
It sounds a lot like the random clunks and ticks one would hear on crappy vinyl during the quieter passages but the sources are all digital.
I, too, tried lower output bit rates without CRC with no improvement.
Then I streamed from my own hard drive audio sources that sound excellent and the new copy did the same thing on playback.
I tried Find & Play for the original file on my HD and it played flawlessly through SoundTap.
So I think bandwidth and volume are not factors.
Obviously, the encoding is going awry and it doesn't realize it.
I rebooted and tried again. No change.