[rbtying]

It's been a long while since I worked there, but IIRC one of the big issues at the time was that the symlink "support" couldn't actually work properly:

- some users want symlinks to be synced as symlinks (and they might not know it, old Apple file formats have internal symlinks), so their files got corrupted if they were accessed on another computer - some users want the sync client to follow the symlink and copy all the files at the destination, which requires the client to listen to filesystem events for potentially the entire filesystem, which is no longer permitted in many cases

so, not exactly a vulnerability, but a mix of security and product issues.