Recently i've realized that this actually introduces more typos -- where a large number of phrases are duplicated or corrected typos reapplied.
There's something wrong with slacks operational transform or CRDT implementation or whatever they use to get edited messages to converge
I'm pretty sure they have none of that, considering you can only edit your own messages. So what's likely happening is that two quick edits are reaching the server at the same time and overriding each other.
I suppose it's possible that the corruption happens on the client side tho --
1. initiate edit action and get editable view of snapshot of text
2. server acks some previous edit request causing some client state related to the message to update and promote a previous edit in some way
3. hit save after finishing editing -- and some delta operation on the client side updates a different message state than the one i initiated edit action from ...
But that doesn't mean my observation of the behavior of the bug is unlikely.
And also -- there is not a hard requirement that only one editor exists -- the same user could use multiple devices at the same time. Consider that and you might find your assumptions to be invalid.
(Where a message sent doesn't match what was typed sometimes.)