Beginning in Apr. 2nd, 2023, Mexico will NOT have Daylight savings time.
Microsoft (and everybody else) has updated their time zones, but it seems that for some reason, SM has not at some level.
Here is the info from Microsoft.
We have extensively test it and it seems to be related to SM.
Test 1.
From account in SM with CST (US & Canada), create a meeting on Apr. 3rd, 10 AM, and invite someone with time zone in Mexico - CST(Mexico, Guadalajara, Monterrey), the event should appear at 9AM, but it appears at 10 AM.
Test 2.
From account in SM with CST (US & Canada), create a meeting on Apr. 1st, 10 AM, and invite someone with time zone in Mexico - CST(Mexico, Guadalajara, Monterrey), the event should appear at 9AM, and it does appear correct (because Daylight savings time for Mexico changed at 2 am on Apr. 2nd on previous years).
Test 3. From Gmail.
From account in Gmail with CST (US & Canada), create a meeting on Apr. 3rd, 10 AM, and invite 2 contacts with time zone in Mexico - CST(Mexico, Guadalajara, Monterrey), one with Gmail, another with SM account. The event should appear at 9AM, and it does appear correct for the Gmail recipient, it appears at 10 AM (wrong) for the SM recipient.
Test 4. From SM to Gmail.
From account in SM with CST (US & Canada), create a meeting on Apr. 3rd, 10 AM, and invite 2 contacts with time zone in Mexico - CST(Mexico, Guadalajara, Monterrey), one with Gmail, another with SM account. The event should appear at 9AM, and it does appear correct for the Gmail recipient, it appears at 10 AM (wrong) for the SM recipient.
In all cases, all the client's computers have all the latest Windows or Mac updates. All have the correct time zone both in their SM account, in Windows or Mac, and Gmail.
SM server also has the correct time zone and all the latest Win updates and we restarted it before the tests.
So in summary, the problem seems to rely on SM.
Ticket raised yesterday.