I scheduler 2 event the first bad record the second ok why?

[armaduk]

Hello i scheduler 2 event in two different channel and sometimes the first record was bad and the second (after 1 hour) it's fine. Why?
the first record is a bad file when i play it i see the screen full of small checks.
The second record is fine.

I have a Lifeview tv walker usb.

Thank and excuse me for the bad language....