Today I made a few changes to my online tree and then did a sync to Family Tree Maker for Mac 2. The change log that popped up showed a lot more changes about to be made than I expected... but I didn't realize something was wrong and I let the sync go ahead.
The result was that the software created duplicates for several marriage and divorce facts on various people all over my tree. I think a few census facts were duplicated as well. About 40 additions in all. Fortunately the duplicate facts created new unresolved places in my Places menu, so I was able to use that to figure out all the people affected (I hope). I then went in and removed the duplicates manually; two hours of my time lost in checking every individual who might be affected and fixing his/her profile.
Upon syncing again, there were no longer duplicates, but afterward some of these marriages and divorces were present in the online tree but missing from the FTM tree. So the only way I could resolve the situation was to make sure the online tree was correct, unlink and delete the FTM tree, and then download the online tree into FTM fresh.
Has anyone else encountered this bug since the update a few days ago? It worries me... I thought the worst that could happen with syncing is that you'd have to unlink and redownload your tree. Having the system actually create facts in random places on your tree is far worse.