In testing the EventLogging for the help panel before the deployment of search, I noticed that many of mobile events were being recorded with editor_interface = "other".
Specifically, the first event (action = "impression") and last event (action = "close") had editor_interface = "wikitext", and all the events in between had editor_interface = "other".
I was using the help panel with Safari on my iPhone 6S in Test Wiki. My editor was the wikitext2017 editor in wikitext mode. I was logged in as "MMiller (WMF)" (User ID 39901). The first event in the series is at 2019-02-12T17:48:02Z, and the last is at 2019-02-12T17:50:00Z.