Could it be there is an issue since the latest release with this Built-In driver?
No, you must have used a different driver for this at some point in the past before switching to the system driver (or another that works differently). To fix, temporarily switch to the "Device" driver and run the "Delete All Scheduled Job" command, then switch back to the Generic Zigbee Outlet driver (or whatever one you wanted to use).
If you didn't hit "Configure" when you switched to this driver before, I'd also suggest doing it after you switch back.
Deleting of the previous scheduled periodic jobs should become a standard function when the ‘Configure’ button is clicked in all inbuilt drivers.
And I think that it is the time Hubitat to think about and write some kind of best practices or recommendations about what the Configure’ button should do in custom drivers.
As per today, the different drivers do different things. It is a widespread misunderstanding that the ‘Confgure’ button must be clicked when changing between drivers, but in many cases it does absolutely nothing useful- especially with battery-powered sleepy Zigbee devices.