Field Maps .pdf attachments download as corrupt .bin files on iPad

[ZacharyO]

We have features with .pdf attachments. These attachments open fine in ArcGIS Online and in Pro. But in Field maps on iPad, they download with a .bin extension and are unable to be read.  this problem is also seen in in FM for Android.

If I save the attachment to the device and rename it as a .pdf, it opens fine.

How do I get it to download and open with the correct file extension so that my field team can view these pdfs?!

Field Maps and iOS are both current versions.

[ZacharyO]

Called ESRI, they said the attachment settings are calling for them to open as applications instead of the file type that they are....they are investigating further.

[sarahc_WellingtonCounty]

Just wondering if you've gotten any updates from ERSI about this issue?

I'm also experiencing this issue on Android. Our field staff need access to PDFs we've been uploading as attachments, but no one can download or access them from their mobile devices. 

[ZacharyO]

It was determined that at the time they were attached (in Pro, I forget which version, though) they were stored as an "application" or something like that Content_Type rather than as a "PDF" Content_Type file. ESRI did not have a work around to suggest other than that attachments made in the current version of Pro are not affected by this and do work correctly. So you can remove and them reattach all your files, or what I did after some poking around was to download the feature service and then field calculate the correct type in the attachment table ("..._ATTACH") then republish the service. 

[Ive_Rouart]

Looking at an answer for why my files are opening as MacBinary on the phone, and it seems to be the same. they are saved as application somehow. but these were added through ArcGIS pro a few weeks ago with version 3.3.2...