Currently, there is no specific information available in the provided context regarding the issue with the "Duplicate Sheet" feature in Excel for iOS. If this feature was working previously and has stopped functioning, it may be due to a bug or a temporary issue with the app. I recommend checking for any available updates for the Excel app, as updates often include bug fixes and improvements.
For more detailed assistance or to report this issue, you may want to reach out to Microsoft support directly or check their official forums for any announcements regarding this feature.
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