Hi,
Do you have Microsoft Teams? It can be from your Microsoft Teams. Please open Microsoft Teams and go to "View Profile". Go to the LinkedIn tab and click (...) More besides your LinkedIn profile. Choose Remove or Wrong LinkedIn Profile. Wait for an hour and see if it has been removed from your Outlook profile.
Also, see if your Microsoft account is connected with LinkedIn.
If you require further assistance, please don't hesitate to let me know.
Stay Safe!