Little bursts of sound in my recordings. Why?

[Doug Swift]

Hi Everyone. I have a DR-60DMKii that I use for documentary work. Lately I've been getting these bursts of sound when my subject stops speaking. Very annoying. I'm new on this forum, so I don't seem to have permission to upload a sample yet, but I will as soon as possible. The mic is a Sennheiser MKE 600. Settings are dual stereo, Gain, mid, Limiter, off, Low cut, off. I'd be really grateful for help.