After exporting my short video and checked it out and it had some shots and some that showed media offline.
I have films filmed with a DSLR camera and an iPod put into one video.
Only the DSLR shots managed to get exported correctly.
If those iPod (you meant iPad, I am guessing) are variable frame rate, they will not cooperate. You would want to convert them to a robust codec/wrapper with a constant frame rate, then replace your iPad shots with the re-rendered constant frame rate versions.
Dell Precision T7600 (x2)
Win 7 64-bit
Adobe CC 2015.02 (as of 6/2016)
256GB SSD system drive
4 internal media drives RAID 5
Typically cutting short form from HD MP4 and P2 MXF.