This is a issue since the Necrom DLC came out and the class still has the same bug, Many people from forum, ingame chat, guild & reddit complains about the same thing. Attacks, primarily Rune Blades, tends to get stuck, almost like its lagging and the server needs to catch up before it registers, making the attack seem unnatural and breaks immersion. The thing is this issue hasn't been replicated with any other classes, its isolated just to the Arcanist Class. I tested various other mmos, swtor, eve online, elite dangerous, ghost recon breakpoint & even Fallout 76 & none of them has the same issues with animations etc so that rules out my network. Especially if its isolated to just one class