I'll try, thanks. For now I can say it's not a sync problem, since it was added days before and I checked the day before, the events were already there.
I don't know if it's the "Ignore all day events", since on another flow that optiont is enabled and it missed just one events since I made it; for now I tried enabling "Debug logging", so I can check what happens with the same conditions, if that doesn't help I'll disable the "Ignore all day events" option, I'll update you.