Initially, Ancestry were unable to replicate the problem I was having with missing media / TreeSync - FTM 2012.
First at Tech Support level, and later at back office (developer FTM) level.
Until I pointed out that they were probably testing "in-house" and not via a typical member experience of having to go via internet.
In-house would have been connected to their Data Center via direct link - and not internet. It all happens in Provo, Utah.
As a retired Systems Analyst, I know how different those two environments can be in developing test scripts. Chalk and cheese !!
My AMT then was downloaded from an Ancestry tech person's own home - and not "the office".
That is when the issue was able to be replicated / observed by them.
The internet link was being timed-out by FTM while downloading media images. At exactly 3 hours.
Having been told that they had isolated the issue in my case, and the fix (among others) would be a part of the upcoming 'update' to FTM 2012 - nothing to be achieved by some of us with issues, until that update to FTM 2012 is delivered.