Same here
Whilst attempting to fix a V-Sync issue I encountered this problem in three of the five back to back missions I played, four of which were the same mission replayed.
It also seems that the alien causing the problem finishes there move between tiles, most noticeable when attempting to target them or they are stood alongside another alien, this behaviour was experienced with Sebillians and Androns in Desert and Industrial areas respectively.
Shooting the alien will stop this sound loop (happened twice) as it plays its recoil from being shot animation, but if you kill it instead and it plays the death animation the sound loop will continue (happened once) until the game is reloaded (SkyRanger_01, Post 3) or the mission is ended.
This problem never appeared during approximately 200 hours of play on V1.09.
I'll be waiting to play this again and hoping this issue is fixed within the next month or so, from a quality assurance standpoint I highly recommend Goldhawk divert resources to solving this issue as it seems rather frequent.
Windows 7 - Nvidia GTX970 - I5-3570K - 8GB - Realtek
Unrelated: The above V-Sync issue was solved by forcing V-Sync on/fast/adaptive in the NVCP, try this if you have scrolling lag on Nvidia GTX970, I elected for fast on a 60HZ.
