Word documents opening as read only in Word app on iPad and iPhone

Many of my new Word documents are opening as read-only whenever I try and edit them on my iPad or iPhone. This is not happening to all of my recent files. It's not even happening to all the files in that particular folder. I can open some older files in the same folders and they are editable, but some files show up as read-only. I can save a copy of the file in the mobile apps and name it the same as the original and then edit that file, but that's a long workaround. Thanks for the help. [FWIW: I recently (last 4 months) got a new laptop, iPhone, and iPad.]