There are known bugs in SmartThings scheduling currently that have been present for months and are proving problematic to fix. This may be the reason. It is making the ST experience very frustrating.
I believe the following applies to ‘Good Morning’ although I don’t myself use that.
One thing you can try is to log into the SmartThings IDE
… and at the bottom of the ‘My Locations’ page click the ‘List SmartApps’ link. You will now see a list of the SmartApps and an entry for 'Good Morning!". To the right of this you will see a button titled ‘Update’. Click this button and it will hopefully clear a problem condition that sometimes causes your next intended event to erroneously be scheduled in the past and hence never run again.
Unfortunately there is no easy current fix for this and it can happen to any scheduled event at any time - so the ST hub really can’t dependably run scheduled events currently which is a pretty fundamental failing ! You can however see the next scheduled run time for any event by clicking on the event name and looking at the ‘Next Run Time’ which should be in the future of course.
See Announcement: New "Update" feature in the IDE