On iPhone 6s (iOS 12, mobile Safari) click on the pencil icon to start editing.
(1) In the editing mode, the pencil icon will present two options - 'Visual editing' and 'Source editing'.
If an article is opened in VE, switch to 'Source editing'. Without making any edits, switch to VE again - the editing mode is ended - the article is displayed in Read mode. Clicking on the pencil button again won't have any effect. The page needs to be reloaded.
(2) The second issue involves interaction with 'Help Panel' .
- Click on the pencil button to start editing an article. Switch to wikitext editor.
- Click on the Help Panel and click in the field to type some text.
- Click 'Continue' and then click 'Back'. Without making any changes in the field close the form.
(Do not submit the question.)
- The wikitext editor mode will display the page without the editing toolbar.
- The page needs to be zoomed in to see the toolbar. Click to switch to VE - the menu looks jumbled.