Error when exporting .pdf file from container field with 'Automatically open"

I am getting an error viewing .pdf and .docx files from a container field. 

There is a button next to the container field that calls the following script:

If [not(IsEmpty(Attachments_C::Attachment))]

                Set Variable [$Path; Value: Get ( TemporaryPath ) & "/" & GetContainerAttribute ( Attachments_C::Attachment; "filename")]

                Export Field Contents [Attachments_C::Attachment; "$Path"; Automatically open]

End If

This all works fine with Filemaker Pro - mac and pc.  If I access the container and save the file(s) to the launch center, I can view both types of files using IOS 9.3.1.

Using the button/script, I can open .doc files but not .pdf or .docx.  I get the following error when opening .docx and .pdf files.

"http://mystaticIP:80/Streaming/MainDB/33844402509131915D9334A3AE302041.pdf?SessionKey=33844402509131915D9334A3AE302041&RCType=EmbeddedRCFileProcessor”

I believe this is failing since upgrading the IOS to 9.3.1.  ( I was pretty sure that it worked before). 

A colleague has confirmed the same issues on his iPhone and iPad (different devices)