Incoming mailbox items redirected to deleted items

Hello,

A user with a mailbox in our Exchange Server 2013 organization receives mail with a subject containing ‘PL-Overleg’. This mail is redirected instantly to its ‘delete items’ folder. This mailbox does not contain any inbox rules.

This issue does not apply to other mailboxes in our organization.

Is there a way to track the root cause for this issue?

Thank you in advance,

Nieck