When making edits on the mobile site, I have noticed that the bar at the top of the screen sometimes becomes hidden as it scrolls out of view so you can't cancel or publish the page. As the UI is designed so only the editing area should move you then have to pinch to zoom out multiple times to bring back in view.
I will upload a screen recording and image of the fault shortly.
iPhone 8 (Model MQ6H2B/A)
OS: iOS 12.1.4 (16D57)
Logged in: Y
URL of page issue seen on in reproduction above: https://en.m.wikipedia.org/wiki/User:RhinosF1/ToDoList#Things%20I'm%20planning%20on%20doing
diff of another time I've seen it:https://en.m.wikipedia.org/wiki/Special:MobileDiff/885370761
Browser: Google Chrome (72.0.3626.101.)