Problem with Shifted Printing

Hello All,
I’m having a strange problem. About halfway through a print job the printer shifted the whole print job by about a centimeter along the y-axis. I can’t figure out what happened. It seems like the belts are okay. Has this ever happened to anyone? How can I fix this?

Here is an image

Its most likely one of 3 things. 1. A loose belt, 2. A loose motor pulley setscrew which shows up as a belt still tight but the print shifts anyways, or 3, an overheating motor controller in the Rambo board. It could also be a computer glitch if you are running tethered, but that is less common. Also a broken motor shaft or siezed idler pulley are possible, but again those are rare.