My son's Vtech VSmile Pocket does this as well.

We only tested his 'Spiderman & Friends' cartridge as that is the only one he plays right now.

We used to hook it up via the front panel on our receiver without problems. This summer I upgraded to the 1070 and now it has the sync issue. The only change in the system is the 1070. Hooking the Vpocket up to the TV directly works without problem. I am using the front panel composite input, and I am outputting SVideo to the television.

Honestly we only do this once every few months, so I'm not hugely concerned, I just wanted to add my experience to the list.

Now if I get another device (DirecTV is getting installed this weekend) and have issues, I'll make sure to get with Outlaw on it.