Has happened on every Mir server where you get displaced and I don't think has ever been found a fix for.
Its main occurrence, is when you get moved by a spell or by push-back (something stood ontop of you) and at the exact same time, you tried to walk or run in a different direction.
Happens loads with Shoulder Dash and Repulse spells because most commonly used displace tools in pvp. One server had a feature where you would type @sync and it would refresh your position, so you would be unstuck, so even if you did get displaced you could easily sync yourself.
Could be worth looking into, and allowing people to macro it to a button as well. Would solve a lot of ranged classes problems with displacement deaths (warriors can simply S-dash out of it)