I am using a Timeline chart in Looker Studio with MySQL data source. The source fields are StartDate and EndDate, both configured as Date & Time.
Problem:
The Timeline chart axis automatically shifts the displayed time by the browser/local timezone offset, but the tooltip still displays the original raw datetime value from the data source.
Example:
MySQL returns StartDate = 24 Jun 2026, 20:32:26 UTC.
The Timeline axis renders the bar around 22:32, which corresponds to Europe/Prague local time.
However, the tooltip still shows StartDate = 24 Jun 2026, 20:32:26.
Expected behavior:
The Timeline axis and tooltip should use the same timezone interpretation. If the chart axis converts UTC to local time, the tooltip should display the same converted local time.
Actual behavior:
The timeline axis and tooltip show different times for the same record. This makes the visualization confusing because the bar position does not match the tooltip values.
Tested workaround:
When I convert the datetime in SQL using CONVERT_TZ(..., '+00:00', 'Europe/Prague'), the tooltip shows the desired local time, but the Timeline axis shifts the value again by +2 hours. Therefore, SQL-side conversion does not solve the issue.
Impact:
Users see the bar in one time position on the timeline, but the tooltip reports a different time. This makes the Timeline chart unreliable for time-based operational reports.
