VirtualDub2 50fps Duplication Issue

[BreadFang]

I've upgraded my capture card to one of them fancy Elgato HD60 X ones, I'm using it for capturing VHS tapes. Before this I had a generic HDMI capture card which worked well enough but could only do 50fps with the older mjpeg format.

I'm capturing PAL tapes and what's always worked before with the older capture device is capuring the interlaced 25fps signal into 50fps, it was always smooth and looked great. But since I've upgraded to the Elgato an issue has cropped up. Now when I capture in 50fps every handful of frames is consistantly duplictaed (or maybe dropped?). It's very noticable.

I'm using VirtualDub2 and the VCR I'm using is a Panasonic DMR-EX95V. It's got native HDMI and Time Base Converter stuff built in (I think?). It's brilliant for capturing VHS (best £5 I ever spent )

Anyone know what's wrong? I never had this issue with the generic brand HDMI card.