Just wanted to say thanks for posting here on this subject. I started having the same stuttering problem, starting getting the same problem from various clients, took a week or so to pin it down. Went to the web to see if anyone else was having this problem and found this exactly as you describe. I hope it gets resolved soon. I've had to turn this module off on over a hundred installations over several clients - VERY annoying.
Interestingly most of my clients are using PCs on Windows Server active directory domains. I haven't heard any complaints nor experienced any problem on any non-dom