Red Line always at left of Art Board

After the most recent update to Illustrator (v 27.3.1), I now have a red line on the left side of all art boards. This occurs when opening any file, even ones created before the update.

The red line is not selectable, I have confirmed that I do not have bleed lines on, and I have tried turning off any guides to see if the line would go away. The red line stays in place and does not follow if I move the art board, but it will return to the left of the art board after saving the file. The red line does not show in preview and hasn't been a visual issue in any of my final PDF documents.

I tried searching for a community post with anyone else having this issue, but I have so far not had any luck, nor found any resolution.

The red line does not hinder my ability to use Illustrator, other than it being an eye sore and a distraction. But, I would love for it to be gone. Any assistance would be greatly appreciated.

Thank you!