Not really a bug perhaps, but a behaviour i didn’t expect.
Please describe what you are doing to trigger the bug:
Testing scheduled backups in WebGUI.
Please describe what you expect to happen (but doesn’t):
If you change the “start at” clock away from 00:00 - then it doesn’t respect the “frequency” - e.g. every 15 minutes.
Please describe what actually happens (the wrong behaviour):
The job doesn’t run every 15minutes.
When you set the starting time to 8:00am for example, then the schedule won’t run from 00:00am to 8:00am, no matter what the frequency is.
Is this the behavior you’re seeing?
I think what you’re describing is what i’m describing 
So if i set ‘every 15 mins’ i would expect it to run every 15 mins regardless of what time is set. If it were set to 08:00 for example, then i would expect it to run at 00, 15, 30, 45, 00 etc 24hrs a day. If i set it at 08:05, then i’d expect it to run at 05, 20, 35, 50, 05 etc.
Then your expectation is different than mine. For me “8:00” means “Start every day at 8:00”. That is independent of the interval. And it may make a lot of sense for a work computer to not back it up during the night, when nobody is using it. But if you want to: Set the street time to “0:00”.
Yes, but there’s no ‘end’. If i also put 15min intervals… when should it stop? I’d argue never. It might be that if my time is currently 07:00, then the schedule shouldn’t begin until 08:00 (the very first time it can run), but from then on it should keep every 15mins - forever.
I think the interface there needs a better ‘workflow’ to remove ambiguity. I believe that there have been other discussions about that section of the UI. In the meantime, perhaps ghosting the interval when the time is shifted away from 00:00?
I agree that having a separate end time would be useful (perhaps call the option "Backup between “start time” and “end time”. However I strongly disagree that it should keep going forever, once it is started.
Again, if you want that, just set the start time to 00:00. No need to deprive others of a useful (albeit expandable) feature.
It’s not that i want it, it’s that it’s not clear what behaviour we should expect. I’m fine with whatever it does, but as a first-time user it would be good to not have to figure that out - so it’s really just a GUI tweak that i think would be beneficial rather than the actual behaviour.