Only when it's breezy. But it's really annoying. And I want to stop it.
The round post that supports the apex (blue arrow) sits inside the square post (red arrow). I suspect it sits on a spring, which helps to buffer the movement of the gazebo in windy weather.
Could the spring be squeaking? Or is the round post rubbing against the square post? Either way, what can I do about it? WD40 is the solution to most squeaks, but is it appropriate in this case?