I just wanted to touch on the 'Third Party Accelerator' issue. This can be caused by a couple of things, but it is likely the after effects of a previous fix to an issue where the animation would fail but still start the skills cool down. It could also be a lag issue, related to your specific connection to the server. Another specific workaround, if you have an AMD system, is to ensure that AMD Overdrive is not enabled in your BIOS and that it's not active via their software. You'll also want to disable CPU Clock Speed Up in the BIOS, if that's present.

That said, if you can submit very detailed reports of what you were doing when it happened - including what skill you used, current fps, current ping, etc. - that would be fantastic. Please use the in game reporting tool to do so.