TellyMate Shield - TV output for Arduino

Has anyone had a problem with the output from the Tellymate doing a continual vertical roll?

I've got this with one particular miniature LCD display with an AV input.
It's one of the "2 AV Input 3.5" Reversing Color LCD Car Backup DVR VCR" that are all over eBay for around $30-35.

However, when used with the Tellymate, the display "rolls" vertically.

I tested the LCD with the composite-video output from my Popcorn Hour network media player - and it works fine with no rolling.

I tested the Tellymate with the 32" LCD TV in my living room. It works fine as expected.

I tried both a Duemilanove w/mega328, and a Seeduino w/mega168. Same result on both (using the "Hello World" and random-characters examples).

Am I out of luck, or is there any way to adjust/tweak the NTSC video timing that's being output?