When running reports using the Trend chart, results based on time may be incorrect due to the 1 hour difference between Daylight Saving Time and Standard Time. This error affects items that are created between the hours of 11:00PM and 1:00AM.
For example, if you want to see all incidents that occured during the previous month, and the previous month was May, all incidents that were recorded between 11:00PM and 12:00AM on the last day of the month would be ignored because the system uses Standard Time. The items would be considered to be part of the month of June.
The issue stems from the fact that records within the SQL database are stored in UTC (Coordinated Universal Time). UTC does not account for DST (Daylight Savings Time). Records are grouped hourly which causes a discrepancy of an hour during the time shift. The combination of UTC and the hourly groupings creates the observed behavior of reports being off by an hour.