Hi Luke,
I tested Ruenel’s code on that other thread on my dev site and it works (display sticky posts first).
A different approach with this (without customazation) is to apply a common category on those sticky posts (e.g. feature posts), then use that category to filter the Recent Posts element.
Sticky posts should be displayed on Blog (news) index posts first by default. Try removing or commenting out the other functions on your child theme’s functions.php file and leave only the code provided by Ruenel, how you added the Featured Articles on top of Blog (news) index might have something to do with this,
It could be a plugin conflict too, please do testing for a plugin conflict. You can do this by deactivating all third party plugins, and seeing if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
Let us know how it goes,
Cheers!