Hi Mark Salsbury,
To narrow this down, could you confirm whether the affected Gmail events are visible when you open the connected personal calendar in Outlook on the web?
If the events are visible there but your work availability still remains free, try removing and reconnecting the personal calendar through Calendar > Add calendar > Add personal calendars. After reconnecting it, create a new test event directly on the primary Google calendar, mark it as Busy, and ask a colleague to check that time through Scheduling Assistant.
If the test event appears in Outlook but still does not block your availability, this would suggest that the calendar connection is working but the free/busy information is not being processed correctly. In that case, please use Help > Support in Outlook on the web and include the time of the test event, as this may require Microsoft to review the synchronization information on the service side.
You can also refer to Microsoft’s guidance here: Show personal events on your work or school calendar. Thank you so much for your understanding.
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