This really isn’t a bug, it’s just a limitation of the dual time zone display.

When you use dual time zones in Outlook and the default zone is west of the secondary zone, an extra hour is added to the time offset for the Sunday DST goes into effect. If you view multiple dates and begin with that Sunday, the (incorrect) offset is used so it appears Outlook has the times wrong.

For example, if your default time zone is Central and Eastern is your secondary time, when Sunday rolls around, the time scale incorrectly displays a 2 hr time difference all day. If you use a multi-day view with Sunday as the first day, the time scale for each day shows a 2 hour time difference.

This view anomaly occurs because the default is a zone west of the secondary and Outlook takes into consideration that DST goes into effect in the earlier time zone and adjusts the times using the wrong offset. The entire 24 hour period uses the same offset and the first day in the view determines the offset. This issue also affects the view when the time “falls back” to standard time, but only if the dual time zones are 3 or more hours apart.

“Time heals all wounds” and it will fix this display problem – until then, use the work week view if you use the dual time zone feature and the default zone is west of the secondary zone.