[Bug] Changing status sets "Completed By" to a random user

We’ve got several stages set as a “Done” state (“On Stage”, “Verifying”, “Verified”) etc.

In our process, prior to release someone will take a ticket through the above stages. However, we noticed that the ticket changes it’s “Completed By” property randomly and assigns someone who was neither the reviewer nor the original actor.

As an example:

Hey Azhar,

How did you update that Status?
I have the feeling you might use a Kanban board, I feel like this might come from the way the list is set up (filters, sections, …)