I'm having the same problem on my BlackBerry Z10 while playing a level (platformer), 10 seconds in and a random freeze occurs for 2-3 seconds. I debugged it, removing large images, optimizing events, then stripping some, I managed to improve performance but the freezing's still there :(
It also happens on the Tizen platform (and also the main reason my game keeps getting rejected)...
I use Chrome for testing, the freezing happens there but for less time.
Using r147, the problem has been there since r130.