That is plain wrong. Hard to believe perhaps, but there are hundreds and thousands of known bugs in all production software. There is simply a prioritization of what is worth doing at a given time. Some bugs will never be fixed, others will. There are for instance about 60 000 open and known bugs or issues at the present time in Chrome - the worlds most popular browser, made by some of the world's best paid talent. So it's just a reality of life: bugfree software doesn't exist.
I know that Sync stored earlier file versions in its .sync/Archive folder, but most people using it does not know. People don't read documentation. So I think that when right-clicking a file in Finder (or Explorer) one should be presented with a way of choosing an earlier file version. The dialog should show these fields for each file/folder When was the file created When was it overwritten by the next version Which peer (user+device) had the change that triggered the overwrite/deletion I know that is what proper backups systems are for, but this eases debugging sync issu