I already posted at similar question on answerhub, but i am not sure if this was the right place or if it is better to ask it in the forums^^
But does someone here know if there is a problem with blendspace driven animations and line tracing in multiplayer?
Depends on how you do the traces.
If you’re tracing up the sword per-frame, its most likely moving past the other sword before a line trace can successfully detect it.
If you’re tracing from several places on the sword from last frame to the current frame, then it should work.
In either case, my suggestion would be to look into using Rama’s Melee Weapon plugin instead, as you’ll probably get better results with less effort 
Thanks for your response
I’d prefer not to buy anything from the marketplace yet^^
And yes I’m tracing from several places on the sword from last frame to the current frame, but I think the hitbox attached to the sword is the problem.
It seems like the position of the blocking sword isn’t updated. If I hit the location where the sword is in idle and/or the arm that is holding the sword, I get a collision with the enemy sword even though it is over the enemys head according to what I see. So the visual and the actual positions are not in sync.