Replaced Right Pulley on Transport Arm - Circles aren't fully aligning now

My glowforge is having issues lining up where the laser starts and stops on a simple circle. We just replaced the right pulley on the transport arm that went and Glowforge shipped us a new one and followed all the directions to adjust the tension on the belt. It is definitely tight enough, there’s no bounce on the back side of the belt while pushing the front side. Is this issue because we replaced the pulley wrong somehow? Or would this circle issue be because of a scratched laser head or something? We cleaned and checked each lens window and don’t see a single scratch. What’s weird is on our K-Cup project that we’ve been printing fine for 8 months before all this started, the stuff closer to the front and back don’t have the issue as much as the circles or cutting of the item in the middle. The middle is where there’s a little lip from the laser coming back to where the circle or cut began.

The intersection of where the laser starts and ends is on the right side middle of the circle.

Any help would be greatly appreciated! Thanks!

That is a mechanical issue. The idler pulley wouldn’t cause it if the belt is correctly tensioned, but the drive pulley could.

I see you already emailed us about this and we’re working on it there, so I’m going to close this topic.