I have read a lot of complaints about AMA unreliable linking in Avid MC/Symphony when people got permanent off-line condition of the AMA ingested footage into their projects.
I personally had Never ever experienced till recently when started using Adobe Premiere Pro CS6 as a supplementary NLE...
I started using the same pool of source clips for Premiere and Avid Symphony projects.
What I realized was the following shocking fact:
if I firstly brought source original files into Symphony project by AMA-linking and then imported the same source original files into Premiere Pro CS6 project, my AMA-linked status of files in Symphony PERMANENTLY went to "offline" status!
Somehow Premiere Pro changed original footage and not just linked to the original file. That caused the Symphony not to see anymore AMA-linked files and I had to re-import original files...
Moreover I found another funny (?) thing about original source files after being touched by Premiere:
the Date Modified shown in Windows 7 Explorer had not changed but the Date was shown changed by the third-party file managing program such as Total Commander v8!
Symphony seems to be extremely sensitive to any information about the file ingested through AMA-linking into its project.
By the way, I could avoid letting Premiere Pro changing original (suppose to be only linked) media by changing the properties of the source file to "Read Only" in windows explorer...
I am going to raise the topic as well at Adobe forums if I find where...
I have used Sony Vegas and FCPX as well and none of them never ever changed original source media.