Problem
"As a delegate of a calendar, when duplicating an old calendar entryupdating an existing meeting, I'm unable to delete or change previous attachments. The The attachments are appear deleted, but once I re-open the meeting or send the new invite using the delegator's account, the attachments reappear."
Solution
This is a known Outlook web and desktop issue and has been reported to Microsoft. As a workaround:
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