Second paragraph in desktop version ends up first in mobile version due to some unexpected placement of a template with .infobox. Compare:
This issue is easy to replicate and an easy to understand test case has been provided:
https://gerrit.wikimedia.org/r/417399 Test case: Don't rearrange paragraphs when infobox does not need to be moved
It appears we re-order paragraphs when the infobox is at the end of the section. We should aim to fix this ASAP. Seems pretty serious.
We know this is impacting Russian sites, but may be impacting many other wikis.