Description:
If I insert certain PDF images I insert into Impress presentation, then export the presentation to PDF (tried with various settings), the images are not displayed in the resulting PDF. If opened in Adobe Reader, it complains that there is an error on the page and it cannot be displayed correctly.

It does not happen to all PDF images, but I noticed this always happens to those produced by ROOT (root.cern.ch). An example PDF image is attached. However if I e.g. process them with pdfjam before inserting in Impress, it works fine.

Steps to Reproduce:
1. Create a new impress presentation.
2. Insert the attached PDF image (by drag-n-drop or whatever)
3. Export the presentation to PDF.

Actual Results:  
The inserted PDF image is not displayed in the produced PDF.

Expected Results:
The image should be shown in PDF


Reproducible: Sometimes


User Profile Reset: Yes



Additional Info:
Example PDF image causing the issue is attached.

Version: 6.0.2.1.0+
Build ID: 00m0(Build:1)
CPU threads: 4; OS: Linux 4.4; UI render: default; VCL: kde4; 
Locale: en-GB (en_GB.UTF-8); Calc: group


User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:58.0) Gecko/20100101 Firefox/58.0