This is caused by the iCloud for Windows add-in. When Outlook syncs the calendar through iCloud, it rewrites the meeting item and removes the hidden Teams meeting data — so the Teams link disappears.
Since disabling the iCloud add-in fixes it, that confirms the conflict.
Unfortunately, there isn’t a real “repair” fix for this. It’s a compatibility issue between iCloud calendar sync and Teams meetings.
Workarounds:
• Keep iCloud calendar as secondary and don’t make it the default calendar. • Avoid editing the meeting in Outlook after it syncs. • Or switch to syncing your calendar directly with Microsoft 365/Exchange instead of using iCloud for Windows.
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