Fasttrack stop working after some time

Hi!

I’m using fasttrack on few of my routers and it works well. But on one of mine CR1072 it just stop working after some time.
Fasttrack connection rule counters are getting hit but dummy rule just don’t show any traffic is passing through it and my CPU raises dramaticly after it stops (which is normal and resonable). Also, if I try to disable fasttrack connection rule and turn it on again I can’t get fasttrack active again until I reboot the router.
I’m using 6.48.6 version.
Does anyone else have similar problem?
Thx

Post your config, please.