Profile Unity RTA

[HVSmith419]

I just purchased a Profile Unity RTA. I am now on my third build, each done by a different person, and every time, within about 18 to 24 hours it burns but only on one side. The other side is completely normal. The first build was in store by owner, the second was by myself, and the third by another employee in the store. Any idea what's causing this? We checked all the obvious problems like loose screws and mesh, cotton, saturation etc