All of the above.
On mine, I had to grind off part of a lip on the driver side axle beam in order for the radius arm to swing completely into place. I think I put photos in my build thread and there is reference to it in a tech article somewhere here on this site.
One of my co-workers tells of his previous job where a maintenance employee who had a grudge against another guy lubricated (coated) the bottom of the guy’s passenger side door handle with anti-seize. You wanna talk about a pissed off wife?
Check the tensioner. You might even be able to clean and lubricated the spring mechanism and make it work better.
It sounds like when the engine first starts and comes up to speed, it pulls the tensioner a little bit. But the tensioner is not springing back into position fast enough. It’s dirty...