Hello David,
Thank you for reaching out. It seems this affects the other date/time pickers too, so I broadened the scope and logged it for fixing. I hope it will get fixed in the next 3.1.0 release as I have proposed to the dev team, considering it is a regression from 2.30.0. You will find your Telerik points updated as a small "thank you" for letting us know.
Regards,
Marin Bratanov
Progress Telerik