Eek. That's not good!
Let me write a test case today.

Thanks for the bug report!

Change 417399 had a related patch set uploaded (by Jdlrobson; owner: Jdlrobson):
[mediawiki/extensions/MobileFrontend@master] Test case: Don't rearrange paragraphs when infobox does not need to be moved

https://gerrit.wikimedia.org/r/417399

@ovasileva FYI. Possibly even unbreak now.

@Jdlrobson I agree with UBN! Content is still visible and the users can still interact with the article but we're fundamentally changing it by (accidentally) reordering paragraphs /cc @ovasileva

Wild idea on how to make this stop for eternity: if we are already using the flexbox for some parts of styling (I’ve seen that infoboxes are using flexbox etc.), there is an option of using it for this. If we wrap the preamble text without an infobox in a container and wrap entire zero-level section in another container, we can use flexbox ordering features for this. Showing in inline styles for example (but of course it should be in MobileFrontend styles).

<div style="display: flex; flex-direction: column;">
	<table class="infobox" style="order: 2;">...</table>
	<div style="order: 1;">...</div>
</div>

Was this an option that the team has considered? It seems like it has a wide browser support (and no related flexbox bugs) and users that use mobile version on higher resolutions may benefit if the change would be entirely visual and applied only to mobile devices (vs tablet, desktop etc.).

Sorry to chime in on this if you have tried it and deemed not good enough for whatever reason. And sorry because this is not directly related to this task, but I thought it was good food for thought for a more bulletproof solution in general regarding this.

In T188825#4039279, @Jdlrobson wrote:

Being bold.. :)

UBN sounds good.

When @Nirzar is done with reading web staging I can point it at Russian Wikipedia to test this change.
Until then this cannot be QAed.

Change 417399 merged by jenkins-bot:
[mediawiki/extensions/MobileFrontend@master] Move infobox only when it's first non-empty sibling

https://gerrit.wikimedia.org/r/417399

Works for me on staging:

Change 419269 had a related patch set uploaded (by Jdlrobson; owner: Jdlrobson):
[mediawiki/extensions/MobileFrontend@wmf/1.31.0-wmf.24] Move infobox only when it's first non-empty sibling

https://gerrit.wikimedia.org/r/419269

@stjn yup flexbox would be the ideal way to handle this, but it involves changing fundamentally how people edit content on wiki. The first paragraph would need to be part of the same flex container:

<div class='flex">
<table class="infobox"><p></p>
</div>

Looks like we've got a fix for this. I will try to get it to go out in a couple of hours during the SWAT window.

Change 419269 merged by jenkins-bot:
[mediawiki/extensions/MobileFrontend@wmf/1.31.0-wmf.24] Move infobox only when it's first non-empty sibling

https://gerrit.wikimedia.org/r/419269

Mentioned in SAL (#wikimedia-operations) [2018-03-13T23:46:54Z] <reedy@tin> Synchronized php-1.31.0-wmf.24/extensions/MobileFrontend/: T188825 (duration: 01m 18s)

The article in the description is fixed.
Not seeing any issues in logstash so pretty sure this is resolved.
Thanks for the report @stjn !