Senddate is altered after import of eml (you send)

Just was pointed to the following issue by an user:
if you save an EML File you sent (lets say 1 month ago) and reimport it, it is put into the drafts folder (which is expected behavior).

BUT:
The send date is altered (even if you pull it to the inbox). To be exact: The senddate is altered to the actual date. E.g. If I sent it on 1st of november export it and import it today, it will be send on 11th of december.

This shouldn’t be that way, because sometimes an email is a important evidence.

Is this happening only in my environment?

Has anyone else noticed that?