I am not certain it is the limbs but I am keeping a close eye on them for any sign of wear. I have also been watching the strings and pulleys. Every screw gets checked daily because the last thing I want is a failure at full draw. A lot of the technology is new to me compared to what I was used to years ago. If I do have a breakdown I will post it.
I personally owned a bowtech invasion for 5 years and never had one issue with it (maybe i got lucky) sold that bow this year and got me a new halon. Couldnt be happier, has me thinking i wont be switching to any other brand for quite some time
I would say if you are hearing any kind of cracking it would almost certainly be a limb issue though, get that thing to the dealer immediately
