Thank you for your post, and I apologize for the late reply.
I am unable to replicate the issue. Here are the steps I took:
1. Using FileMaker Pro 12 under Windows 7, I created a database file with two Container fields named "Container File" and "Container Interactive".
2. In Layout Mode, I set the formatting for "Container Interactive" for Interactive content.
3. In Browse Mode, I added one record. With "Container File" active, I pulled down the Insert menu and selected "File...". I inserted one of the FileMaker PDF files (Acknolwedgements). It appears as a PDF icon.
4. With "Container Interactive" active, I pulled down the Insert menu and selected "PDF...". I inserted another FileMaker PDF files (Read Me).
5. I turned on Network Sharing for All users.
6. I closed the file and quit FileMaker Pro 12.
7. I manually moved the FileMaker Pro 12 file to Windows Server 2008 R2 machine running FileMaker Server 13, and placed it in the Databases folder. I launched Admin Console and opened the database file.
8. On an iPhone, I launched FileMaker Go 13, accessed the server and opened the database file.
9. I tapped first in the "Container File", tapped View, and the PDF file is displayed.
10. I tapped the "Container Interactive" field, tapped View, and the PDF file is displayed.
11. I closed the file, and exited the application.
12. I launched FileMaker Go again, accessed the file, and I can tap and view both Container fields.
Let me know what I'm doing differently than you so I can replicate the issue.