Sticky air damper, Lopi Endeavor

Wonder if anyone has had this happen? Having issues with the primary air damper on my Lopi Endeavor in that the rod is very difficult to move. It sticks, jumps and starts, which makes it hard to accurately regulate. The stove is only three weeks old and this has become progressively worse. It started just a as a noisy damper in the beginning, and this morning it was almost stuck in the closed position when I went to reopen it. The temps were about 550° when this happened this morning. It usually gets worse as the temps get higher.

Same thing happened to my liberty so I got some dry graphite lubricant and put some in between the air control slider plate and it help a lot although its still a little sticky.I want it that way so It harder to open if it accidentally gets bumped. It could also be some weld residue causing the resistance which can be removed with sand paper I think that's what I have read on here. Is it real easy to open and close when the stove is cold? I could be an ongoing problem just from the hot stove expanded.

Thanks, that makes a lot of sense. I'll look at it and see if it is from a weld or if graphite will work.