To start with I have Sky coming though Vodafone cable. So, this could actually be a Vodafone (not Sky) issue.
On Sky Sports HD channels 54 (Badminton) & 55 (Swimming) the live feed is having issues. The audio is intermittently pausing, and I have noticed on a couple of occasions frame strutter.
Curiously, the Bowls on channel 57 (also live HD) isn't suffering the same problems. Another channel which is broadcasting pre-recorded content is fine.
Note: I have an HD ticket for all CG channels (for what that's worth).
Anyone having the same problems?