The home page of one of my courses was changed. I went into the history to change it back. None of the the co-instructors was listed as the person who changed it, there was just no name, How did this happen and how do we avoid it in the future?
I suggest asking your canvas admin about any settings they may have made to your (or all) courses. If it was not an instructor, the admins should be the only ones with access to make changes.