Probably not. I've run into something like this before and I suggest that it is a limitation in the PDF file structure. I've never successfully pinned down the cause, or made a successful resolution to the issue. I do make doubly sure students are aware they must download and then edit and save in Acrobat, then upload.
<span type="embarrassed whisper">Alternatively, I think I did once... mmm.. maybe twice... maybe... made the mistake of opening the unedited file, the one the students were to download, edit, save, upload, to try and grade that... still not sure how I managed to do that, but that was really annoying at the time. So trust me, I know what I am doing..😱</span>