Broken threading for mails without subject

Hello there,

This has already happened a few times for me now. When I receive an email with an empty subject and I reply to it, my reply doesn’t go below it in the message thread.

When this happens, I can find my answer and all subsequent emails exchanged in the Sent folder, with a subject of “Re: No Subject”.

So it’s only the threading between the initial mail and my initial reply that doesn’t work.