txt attachments not showing up in Collector (iOS)

Question

I have a hosted feature service set up with plain text (.txt) attachments.  The attachments are not showing up in the Collector app for iOS.  They show up fine in Collector on Android.  Any clues as to why this may be.  The text file names are rather long (29 chars).

Anonymous User · Answer

Follow-up II: If I edit a feature, the txt files show up in the list of attachments I can delete. They still do not show up in the pop-up when not editing.

Anonymous User · Answer

Just a follow-up: The length of the filename doesn't make any difference.  Also, plain text files (.txt) show up as attachments in Workforce.  Why not Collector (iOS)?