When editing a wiki, it doesn't autosave when changing teams with option-up
(macOS Mojave 10.14.4, Microsoft Teams Version 1.2.00.8866)
Normally when you're editing in a wiki, it auto-saves. If you're in the middle of editing, and click on another team, it will have saved everything you have done.
But if you're in the middle of editing a wiki, and click OPTION + UP ARROW, it will go to another team and you will lose all your work in the wiki.