Lost SR for leaving but never put in match?

When you disconnect, the server does not immediately remove you from queue. In fact it can take up to 45 seconds before the server considers you to be disconnected and you can still be queue for a match during that time. Unfortunately all disconnections and game crashes counts as leaving the match and will be penalized appropriately. The game server has no way to discern a legitimate disconnection or game crash from one that is forcefully caused by a dishonest player to bypass leaver penalties. You can learn about this policy here: