You may have noticed that your Calendar looks weird and the half-hour lines on the left are all skewed by 5 minutes or some other random number of minutes (e.g. 8:05 am, 8:35 am, 9:05 am etc).
This is because you have a setting in your Calendar filters, to show available hours only.
When this setting is enabled, Calendar will show only the hours available in your shift, plus it will stretch beyond the shift to accommodate any events created before or after available hours.
The day will start at the start of the earliest event for any of the team members selected in your Calendar Filters.
For example, this task on the left was scheduled for 6:05am and now the whole day will be skewed by 5 minutes:
The simple solution to this is to move the offending task or appointment to a round time, like 06:00 am or 6:30 am.