Mountain bikes with carbon frame and quick release axles and trailers: will I need spacers

I have a quick question: I bought a “new” used mountain bike and I plan on hitching my bike trailer, a Burley Encore, to it. Currently, my mountain bike has an aluminum frame, so I just put the metal bracket in between the quick release nut and the bracket, and tightened up the quick release axle with the bracket directly against the frame.

But the frame of the new bike is made from carbon (also with quick release skewers), and I was wondering whether I should put a spacer or a washer in between to protect the frame. Does anyone have ideas or experiences here? I checked Burley’s quick release hitch guide, and it doesn’t mention carbon.