To me this seems like some kind of priority issue at the server end or else cooldowns are triggered client side without any confirmation response from the server (extremely silly if that's the case). In issue 1 the server gets the second ability request while processing the first so the second request gets dropped but cooldown is triggered BEFORE the ability so you still lose the cooldown despite the server erroring on the ability. Issue 2 is if cooldown is triggered client side. You click the ability and as long as it's available to use it resets cooldown regardless of response from the server. Either one should be fixable so here's hoping they have something in the works for 2.1 I can see where this could require a large amount of debug on the dev side which may be why it hasn't been hotfixed. It isn't easy to test issues tied to networking on a dev build of a game you're playing over LAN or even connected to a dev server at the datacenter since the server wouldn't be under load.