I don’t know if it is a common issue, but I have a month old Support ticket on this issue that is still unsolved. In my case, it was narrowed down to time-based Routines that were failing to change Mode (all other actions in the Routine executed correctly). Presence-based Routine triggers (e.g., “when everyone leaves”) worked, and continue to work. For the time being I have moved my time-based Routines to a smartapp, Rule Machine.
If your problem is similar, please open a Support ticket and reference mine, #154180 (open a trouble ticket in any event). Maybe if enough people complain about this they will do something about it.
My routines seem to work although if you set a time for a routing to happen at you need to make sure its set for an hour earlier than you want. Its a known BST issue " I think"
The only way to get it to work it to set up your routine the day before you need it, let it work, then delete it and set it up again. As it just doesn’t work. Someone on here today advised me to try Trigger Happy App so I have replaced my time based routines with that and will see how that works.