There is something structurally wrong with the way things are done in this company, period. I suspect the manager in charge of programming has not been fired and has his/her manager convinced all is well with sync. There seems to be no other logic to apply.
I would secure a good copy of your tree. Place it on Ancestry and FTM separately and pretend the sync feature does not exist. Yes, some people say that they have no problems with sync. But if many others are having problems, there is something basically wrong.
A program should either work or not work.
Kudos to those who persist in forcing the programmers to fix the programming problems. I think they need to scrap FTM 2012 and start over, with new competent programmers who test their program before release to the public!