At some point, it looks like Stalker can get stuck during an LMB: he'll pull the blade back but never let go of it. Hitting LMB again won't do anything and cause a weird noise to repeat over and over. I'm not sure what causes it, and its been hard to get out of though hitting a skill like Q seems to get me out of it sometimes.
#Stalker LMB Gets Stuck
sterile nexus
olive pelican
This happened too me a lot while playing Stalker as well.