Version: 20.2.21 (E. 7.1.8)
Build: 35 (rev. 2722aeb6)
I typed a very long message into the app. Sent it. Saw a typo. Edited the typo. Hit save.
Result: message disappeared. No one can see it now.
Expected result: message did not disappear.
I'm mighty cranky about this. That was a long message and now it's gone.