Hello @Polat, Nezla,
Thank you for providing such a detailed description of the issue. After reviewing and working on it, we’ve determined that the unexpected behavior where an item's property in SharePoint does not recognize the correct content type is typically related to a server-side process and it requires involvement from our backend team, which is beyond the access level of Microsoft moderators. They will need to check the site configuration and document library settings from the backend to identify the issue and apply the necessary adjustments. To submit a new service request to Microsoft Support, you will need to:
- Go to the admin center at https://admin.cloud.microsoft. If you are not the admin, please help us to contact directly to your IT Admin.
- On the bottom right side of the page, select Help & Suppport
- Please follow the structure below and select "Contact Support". Then, choose contact method: "Phone" or "Email"
- Enter a description of your issue, confirm your contact number and email address, select your preferred contact method, and then select Contact me. The expected wait time is indicated in the Contact Support pane.