Duplicate Absences in Outlook

Good Morning,

I am using the Personio API to import absences into Personio. However, I have encountered an issue: there doesn't seem to be an API endpoint for updating an absence, possibly due to the approval workflow. As a workaround, I am deleting and re-inserting the updated absence.

Additionally, we have activated the Outlook synchronization feature to display absences in Outlook. This has led to another issue: each cycle of deleting and re-inserting an absence results in the absence being duplicated in Outlook.

I have two questions:

Is there indeed no way to update an absence via the API? If there is, how can I do it correctly?
Why are absences being duplicated in Outlook?

I believe I might be missing something. Any guidance you can provide would be greatly appreciated.

Thanks and kind regards,

Alex