There is a known issue with file upload fields in Instagram’s iOS app (as of June 2018) when a link is clicked from a direct message. When a user opens a link from a direct message, the file upload field displays, but when they select a photo to upload, it shows briefly and then is removed making it impossible to submit a photo. This appears to be a bug in Instagram’s in-app browser implementation. The problem does not occur when links are clicked from the profile bio section.
Updated on October 31, 2018