saa7134 + xc5000 long time work

Hi

One of our customers report me about a strange bug. They use our TV card with DVB-T for capture a DVB-T signal and transmit it to his network. TV card based on saa7134, xc5000, zl10353.
Main problem is: after 30 day of 24h working TV card can't lock a DVB-T signal. After rebooting all is normal. Does Anybody have same as problem?

With my best regards, Dmitry.