Thunderbird does not sort by "Received", instead it uses "Date" for both sorting options
It seems that Thunderbird looks at the "Date" tag instead of the "Received" tag, even in the "Received" column. The effect is that SCHEDULED emails from somebody appear way down the list at the date it was originally written (saved in the "Date" tag).
When looking at the Date and the Received column, the date is the same in both, despite the email being sent and received days after it was written.
Example from the email's source (scheduled on Sept12 to be sent on Sept15):
Received: from dm5pr1601cu001.internal.outlook.com by MWHPR11MB1374.namprd11.prod.outlook.com with HTTP via MWHPR10CA0007.NAMPRD10.PROD.OUTLOOK.COM; Fri, 15 Sep 2017 14:08:50 +0000
[...] Date: Tue, 12 Sep 2017 19:08:49 -0700
I'd file a bug report, but I didn't have time to go through all the documents for such an easy to fix problem.
Best, Sebastian