Tightrope:
,,,,,, I had a friend on Skype sending chat messages - I grabbed the swing icon to start a shot, said "send!", and waited. Nothing happened. As soon as I released the shot the messages came in. Same with online/offline, nothing happened while the swing meter was in action.
I believe a friend list update that occurs just before we grab the swing meter can cause so much work for Flash that it causes the meter to stutter on the swing. I gave a somewhat technical explanation how I think this happens in Flash in this post last September.
I did a similar experiment as you did on Skype. But I was trying to cause a friend update just before the swing began. I had a friend on Skype ready to start his swing. I changed my on-line status then said "swing". Amazingly, his meter stuttered on the first attempt. Overall, due to the various timing considerations, I only made his meter stutter 2/10 tries.
WGT needs to give us the option to turn off friend updates during our games.