verifyRunRules validates that only the expected attributes ('dom', 'dow', 'hours', 'minutes') exist, but doesn't validate the list of values are in the expected range (0-59 for minutes, 0-23 for hours, etc)
Thank you for reporting this issue, it has now been resolved. We are aiming to include any changes that have been made in a future XF release (2.3.0 Beta 7).