When students upload papers to Canvas, they can upload revisions as many times as they want up to the due date.
Recently, one student's paper was marked with an 86% score by Turnitin, and it seems that this was based on comparison to an earlier version of the paper by this same student (submitted just minutes earlier). When I look at that version, it only has a 2% score.
I have been using Canvas and Turnitin for a few years, and have never seen this (and students do frequently resubmit). What could cause this to happen?