Hi email@example.com. That is interesting. In one of my sandbox I tried a couple of different ways to replicate this with fake student submissions and wasn't able to replicate how your image above appears. I wonder if it could be something related to a particular browser (I only tried with Chrome)? You could contact Canvas Support to get their take on the situation or if it isn't causing any problems wait and see if it continues in future student submissions. If you do find out what is going on, please let us know!
Thanks for the information---