HLS jumps or keyframes lost on iOS

HI, I am tetsing with FMS 4.5 and we notices that we are having problemas with HLS on iOS:

The streams works great, but when you are listening on iOS you can hear little silence or like the songs jumps. I think that it could be when FMS join one hls file with the next.

I have this from 1 year without solution.

Any help?

thanks