It would appear that using “drag and drop” ordering of featured articles isn’t “sticking”…

Expected behaviour:
"Drag and drop" ordering of featured articles should “fix” and be replicated on the frontend.

What happens:
Article order can be changed on admin by “drag and drop” and looks okay, but it reverts to the original order when navigating away.

To replicate the the issue:
In /administrator:

1. Order your Featured Articles using the “drag and drop” interface.
2. Navigate away from the page and then navigate back.

The article order will have reverted to its previous state.

Please note:
This is an upgraded site, i.e. J5.4.0 —> J6.0.0

Confirmed by another user on Joomla Forums:
https://forum.joomla.org/viewtopic.php?f=860&t=1021040