I too had a decent round going last night, with everything working smoothly. Then, I was just about to tee off on the 9th hole when I noticed a hesitation as I started my backswing.
I looked down at my laptop and noticed the disk light was on solid. So, I waited.
This has happened to me before. I've used the Task Manager to find out it's Microsoft's anti-malware stuff going off about something. So, when it happens, I just wait a few minutes and the system settles down and I can continue.
Now, this could be a problem when playing with others as you can't wait too long, but it's still not WGT's problem. It's mine.
I have even learned to wait before I start my swing after I've done my set up. I've noticed that right after switching views, for me at least, the hard drive will be accessed a few times, which could potentially cause a hesitation of the swing meter. So, I finish my set up, wait a few seconds, sometimes even check the disk light one more time, and then I start my swing.
There are way too many variables from PC to PC, plus the internet and so on, for WGT to be even remotely responsible for the occasional jerky meter. I accept that and I deal with it.