Blob triggered Azure Function not executed when Blob is uploaded by certain user. The Blob Created Event is matched and delivered as expected.

Question

I have set up an Azure Function that is triggered by Blob Create Events via an Event Subscription.

When I upload a file to the container, the Blob Creation Event is published, matched and delivered, also the Function is invoked and the file gets processed as expected.

When a colleague uploads a file to the container, the Blob Creation Event is also published, matched and delivered but the Function is not invoked.

I have already checked that the Blob types of both of our blobs are the same (Block Blob) and I have already tested different upload methods such as uploading via the Azure Portal and SFTP. I can not replicate the behaviour my colleague experiences.