I was trying to add some links to the header of Talk:Flow on ee-flow labs instance, and the wiki text kept getting garbled -- letters would appear in the wrong place, links would get lost. You can see this if you click the pencil to edit it (Don't save, we need that text!).
I pasted similar text into a post and that appeared garbled, see http://ee-flow.wmflabs.org/w/index.php?title=User_talk:Spage&workflow=0508e9b63c8f34dffb6efa163e68c4ac. It has the wiki text
- report bug in [https://bugzilla.wikimedia.org/enter_bug.cgi? MediaWiki's Bugzilla] if you can
On edit this turns into
report bug in [" test wiki for the [[mw:Flow_Portal|Flow pro MediaWiki's Bugzilla]
This is not only garbling text, it's also introducing random bits of text that resembles my other recent edits. Maybe a caching issue?