Tab between 'start at' and 'end at' fields for time tracking

Our board has a Time Tracking column. The input displays a calendar with ‘start at’ and ‘end at’ fields. However, whilst it is possible to tab from the hour field to the minute field within either start or end fields, it is not possible to tab from the ‘start at’ field to the ‘end at’ field. When retrospectively recording multiple entires clicking between the two is frustrating and it seems like it should be an easy fix?