So the game doesn't seem to cope very well with frequent fast movement.
I've been running a dual daggers Shadow, and since I've mostly been focusing on offense so far I've been relying on Whirling Blades as a sort of active defense (for those unfamiliar: it's basically a teleport type skill where you rush forward and damage anything in your path). Not just firing it once to get out of a sticky situation mind, but spamming it back and forth repeatedly as a standard tactic.
When it works, it's great, enemies die, I don't. Plus it's kinda fun visually, a sort of Nightcrawler-esque port fu: warp in, stabbity the annoying necromancer, then immediately warp over to the archers and stabbity them, then warp all over the melee guys in a blur.
But as I say the game doesn't seem to cope with it very well: despite my latency being consistently under 50ms, when I use Whirling Blades more than a once or twice in succession (and sometimes once or twice is enough) I guess I desync, because it stops registering hits on the enemies I 'whirl' over, and worse I start rubber banding something fierce and have died more than once due to warping out of danger, only for the game to throw me back into certain death (including one occasion where I narrowly escaped a horde of those suicide bomber guys, and the game helpfully rubberbanded me back into their midst right as they exploded).
I'm hoping this is just teething troubles and it'll improve with time, but from what I gather desyncing has been a long-standing problem, unrelated to individual connection quality, so I may have to shelf the Shadow