There is a daylight saving time display "bug" that affects both Outlook for Windows and Outlook for Mac. It's not really a bug, but a limitation of the capabilities of the time scale and only affect people who start the week on Sunday. It's also more noticeable if you use Outlook for Windows with two time zones enabled and the default zone is west of the secondary zone. There are also display issues when the time zones switch to (or from) daylight saving time on different dates.
In all situations, opening the appointment will show the correct time.
Solution: Use the work week view, the day view, or start the week on Monday… or use any view that doesn't start on Sunday.
When Outlook starts the week on the Sunday the week the time changes, the time scale will use the scale in effect when the clock rolls over to Sunday, not the time scale that is in effect most of the day. When you use the week view, all events the entire week will appear to be off by an hour when viewed in the weekly calendar.
If you happen to use dual time zones in Outlook for Windows and your default time zone is west of the second zone, an extra hour is added to the time scale offset for the Sunday DST goes into effect.