Of course this will not be representative, but it might be worth a try.
If and only if you have been adding any attachments at all, on any platform, would you please respond to this post with just one line and the name(s) of the platform(s) on which you are using Joplin. So your answer may / should read :
Android ( or Win, or iOS ... ) OR
Android / Win10
Please do not add comments, questions, or explanations.