There is a known issue with events happening twice for a few people right now, due to some back end work.
As they announced previously, smartthings is changing the way they schedule some events in order to try to prevent the sunset problem where not all events fire.
Consequently, they are moving members from servers that use the old method to servers that use the new method.
This can result in an individual household temporarily having their schedules stored on two servers. If this happens, events may fire twice.
It’s not clear how long “temporarily” is, or how much it varies, but at least one member reported problems that lasted almost 24 hours.
So just in case that factors into anything you’re seeing.