I am having that problem also. Worse It may be intermittent. However, you might want to clean these:
https://community.glowforge.com/uploads/short-url/v4s6q5ULHwtYKuVG9msvfjz8atn.jpeg
and check out this thread…Head fan weak? as well. they said that they checked and all was good, and it was for a bit, but then went back to its old ways.
There is a tiny fan in the head that will create enough drag to make the larger fan spin a bit if it is not blocked. I put a vacuum hose up there to try and get any other junk from it, but even at best it was not blowing like when it was new.