I recently had this bug appear in a Photoshop. A portion of one of my text entries created a repeating pattern of one and a half of the letters, and started appearing on multiple layers. Even appearing on new text created. It has now spread to a seperate Photoshop file, even though I never dragged anything from the corrupted file to the new file. Here's an image of the issue.
It's currently appearing on a Smart Layer, though it isn't present inside the Smart Layer itself.
Has anyone seen this issue before and figured out how to address it? I can't find anyone else describing this issue in other posts.