Noise coming from the rear when the ICE kicks on

Hi, so I got my 2017 Volt last month, and I recently took it for my first long trip, requiring frequent ICE useage. I noticed that every time the ICE kicks on at low speeds (20-30mph, while accelerating) there is a relatively loud clank noise coming from the rear...maybe rear passenger side. To me it sounds like the muffler is jumping around back there and hitting things (sounds like someone hits the muffler with a hammer when the ICE turns on). I googled a bit, and I see quirkySquirt has some stuff in their signature that might be relevant, but I haven't made enough posts to see his signature so I apparently can't look at it.

Anyways, is this something I should be worried about? Any way to fix it?