Damir What you describe is exactly why I will never auto sync. So many pitfalls. Imagine you are out on a gig, you turn on your ipad, and files are missing because either, you lost connection, you forgot you updated some songs on your imac at home, your iphone is playing up, you are low on battery and your back up didn't sync as expected, and likely many more scenarios than I can think of, for sure. I will never understand how anybody can trust this random flow of cloud-exchanged data, and having hundreds of ppl depend on you and your performance. Totally beyond me.
When the sync feature came, my imac's OS Big Sur 11.7.1 was not even able to sync. Red files everywhere. Who is to say when the next OS sync problems will show in the future? All sane and pro gigging musicians here will make a back up anyway, so for me, waiting a few minutes to manually restore/update the data is safe, secure, and totally worth the wait. My 0.02$.
Having said that, I switched to ST3 May of last year, and not once has it failed me. Not a single beat. It's an absolutely fabulous piece of work from Peter. But then, I keep it simple. Manual updates only, an airturn for stop/ start and loop, and no fancy dancy midi programming. Did that for 20 years, TC Helicon for harmony and effects, and Dashlight for programming lights. What a lot of wasted time! My advice is to keep things simple, save yourself time from all the bells and whistles. If you can sing and play, the audience don't care if your lights are flashing, your guitar has the right overdrive, or your harmony is there.