About an hour ago we isolated these two causes of Blocking/Stucking/Targeting in-game as you refer to them, and knowing is more than half the battle for us. These aren't trivial to fix, and will require some extra testing to ensure we don't sacrifice stability in the process of fixing them, but this category of bugs just got a big red target painted on them.
In the meantime, you will see some improvement if you avoid targeting in the center left of your screen during chat, and abilities will fire more consistently if you issue a move command (as opposed to an attack command) prior to activating them, especially when pursuing or escorting a target.
FWIW, if you see a bug in-game and are REALLY passionate about helping us fix it, try to get what we call "100% repro", which is basically a step by step chronological list of the bare minimum things to do that will make the bug happen every time.
Try to eliminate unnecessary steps in the process, but don't leave out anything during game setup, those are often most crucial. Also avoid steps like "Play for 30 minutes". That is so nebulous that it hurts my head, and the number of things that can happen to taint the evidence during long lapses is exponentially infinite.
Obviously we aren't expecting everyone to spend time helping us make the game better in this way, it is our job afterall, but we can fix things so much more quickly when we have a clear understanding of the issues like this one.
"Light Catapults have joined the battle"
- Servo
