Go to:
https://en.m.wikipedia.org/wiki/San_Francisco
Click/tap on an image (the lead image in the infobox will do)
You are taken to:
https://en.m.wikipedia.org/w/index.php?title=San_Francisco&renderZeroRatedBanner=true&renderwarning=yes&returnto=%2Fwiki%2FFile%3ASF_From_Marin_Highlands3.jpg%3Facceptbilling%3Dyes
However, you should be taken to the image's file page.
Similar results happen consistently for me on any image I try, either in Chrome on Android 4.2 or on Chrome on OS X.
I suspect this is a result of some Zero-related code leaking for non-zero traffic.
Version: master
Severity: normal