Lately I’ve been informed of seemingly strange users behavior in teamgames :
- Freelosing (leaving within the first seconds).
- Teamkilling : worker-rushing his own allies.
- AFKing : staying deliberately in the game for the first minutes, while not doing anything.
In the last case, we’ve had an example of an user probably botting to do so (the pics have been anonymized of course). And it became clear the intent was to smurf more efficiently, as contrary to 1v1, freelosing in the first seconds does not always causes defeat (= MMR loss). So that player stayed for 5:23s each game to ensure his resources were not shared, to maximize the chances of defeat (and thus tanking his MMR more efficiently).
It was a fully deliberate behavior. And though anger might be a motivation in some cases, I suspect teamkilling might be another way to achieve that same result than the AFKing method. Do you by chance have any replays left of one same player attempting to do this ? If yes, could you place yourself in his vision, and see how much variability there is from one replay from another ? If you still have some matches in your history, watching how long those teamkills have been played in a row from that user would also be informative. 
Do not post them directly here though, unless you know how to anonymize them (if you want me to analyze them we’ll have to discuss a sharing method). 