When I loaded [[mw:Mobile wikitext editing]] recently as a logged-in user, the page looked completely blank. This may be an issue in VisualEditor, I'm not sure. Purging the page fixed the issue.
My suspicion is that Parsoid somehow returned blank content. Unfortunately I'm unable to reproduce this issue.
Version: unspecified
Severity: normal
URL: https://www.mediawiki.org/wiki/Mobile_wikitext_editing
This is the Parsoid output: http://parsoid-lb.eqiad.wikimedia.org/mediawikiwiki/Mobile_wikitext_editing?oldid=889921
Client-side VE issues typically result in JS errors in the browser JS console. Could you check whether that is the case?
Without a way to reproduce this or some kind of error log we can't really do anything here. There have also not been any other reports about blank pages, so closing this bug as worksforme.