We have seen this same problem and while I don’t have a complete solution, I have one menu setting to check that may help. On the front soft menu (I think it’s page 2), look for the LTC/VITC button. It’s not down in the scrolling setup menu, it’s one of the soft keys. Toggle through and try each of the three options, for us “Auto” seems to do the trick but one other poster suggested that the VITC is being copied from your other deck; in which case you may need to force LTC.
Just kind of a shot in the dark, but good luck!