Sorry in advance for the bad video quality, I do not have a capture card and my phone was the only way to record. Anyway...
This glitch has been around since Gears 2. In Gears 1, this glitch did not exist. What happens is when you are playing local or as host in a private game, your character will make a grunting sound when slamming into cover.
Now, I went into a quick match Warzone where I was thrown into a match in progress; I assume on dedicated servers. Here's a video of me slamming into cover as a Locust.
And another video, just to be sure: http://www.youtube.com/watch?v=LNoSUxVlAHU
I know this glitch isn't huge, I just wanted to point it out. Let me know if you've encountered or noticed this, or if it might just be a problem on my end. Thanks.