When using Default Timezone the date/time fields have time reduced by 1 hour when setting dates from April 2nd onwards.

Issue Summary

When using Mexico's default time zone in Jira, date/time fields are reduced by 1 hour when setting dates starting April 2nd.

This may be caused due to Daylight Saving time. However, the Mexican Government has declared that Mexico will only have one Standard time from 2023, and the time will not be adjusted as per DST adjustment.

Time-related data are getting affected, thus impacting the business.

Steps to Reproduce

1. Set the Atlassian Account timezone preference - or Default user time zone on Jira General Configuration - to (Mexico/Mexico City GMT-6) 
2. Try to set any Date/Time field starting from April 2nd.
3. The time will be reduced by 1 hour.

Screen recording of the problem experienced: Incorrect Time on Fields due to the Daylight Saving Time

Expected Results

As Mexico eliminated the DST (Daylight saving time), no automatic changes should occur to the time set in the date/time fields.

Actual Results

When using the Mexico timezone, if I set a field with the following information: April 3rd, 2023, 10:00 AM, the time will be automatically updated to 09:00 AM.

Workaround

The only Workaround identified at this point would be using a different Time zone with a similar GMT in which Daylight Saving rules are not applied (for example, Guatemala GMT-6).