So, the story as best I can determine:
The symptoms I originally posted seem to be isolated to just one of my AMTs that was then synced to FTM2012. Further investigation reveals that while the AMT source citation details are correct on the linked ACOM source (to the right of the Residence fact - 1 source citation - then clicking on the sideways leaf link - where you see the index information with the source info at the bottom) it appears that the source citation details recorded on the fact do not contain the citation details (clicking on Residence then at the bottom - Residence Source Citations).
The result is that when the AMT is exported to a gedcom, or indeed apparently when synced to FTM, the corresponding 3 PAGE for the 2 SOUR does not contain citation details. Deleting the Residence fact in the AMT and re attaching the 1910 census source corrects the problem (both in an exported .ged as well as a newly synced FTM tree). It appears to me this is an AMT issue and not anything to do with FTM2012.
The question is just how the AMT ended up with 1910 citations all messed up. Could be that sometime in the past I exported the AMT to .ged and re-imported the .ged creating a new AMT. Doing that today as a test did not duplicate the problem. All are probably aware that AMT export to .ged has been broken many times over the years; perhaps during one of those times 1910 census source citations were messed up - who knows.
I have a couple hundred 1910 citations to fix so it's a toss up whether to try and automate the process or just manually fix them one at a time. Bummer.
The symptoms I originally posted seem to be isolated to just one of my AMTs that was then synced to FTM2012. Further investigation reveals that while the AMT source citation details are correct on the linked ACOM source (to the right of the Residence fact - 1 source citation - then clicking on the sideways leaf link - where you see the index information with the source info at the bottom) it appears that the source citation details recorded on the fact do not contain the citation details (clicking on Residence then at the bottom - Residence Source Citations).
The result is that when the AMT is exported to a gedcom, or indeed apparently when synced to FTM, the corresponding 3 PAGE for the 2 SOUR does not contain citation details. Deleting the Residence fact in the AMT and re attaching the 1910 census source corrects the problem (both in an exported .ged as well as a newly synced FTM tree). It appears to me this is an AMT issue and not anything to do with FTM2012.
The question is just how the AMT ended up with 1910 citations all messed up. Could be that sometime in the past I exported the AMT to .ged and re-imported the .ged creating a new AMT. Doing that today as a test did not duplicate the problem. All are probably aware that AMT export to .ged has been broken many times over the years; perhaps during one of those times 1910 census source citations were messed up - who knows.
I have a couple hundred 1910 citations to fix so it's a toss up whether to try and automate the process or just manually fix them one at a time. Bummer.