Image size calculation for the source article happens in a wrong timing causing wrong dimensions for placeholders in translation column

After login, one can see it here http://language-stage.wmflabs.org/wiki/Special:ContentTranslation?page=Flute&from=en&to=es. Try clicking on the '+ Add translation' placeholders.

Expected result: Correct alignment for all sections in the document as documented at https://www.mediawiki.org/wiki/Content_translation/Section_alignment

Version: unspecified
Severity: normal