Help deinterlacing capture with strange chroma problem

[18fps]

I'm trying to deinterlace this film (VHS PAL Capture), but even doing a simple SeparateFields() I see a strange chroma problem. It's as if the chroma were temporally displaced half a frame or something like that. It's noticiable specially on the change of scenes. I'm including here a very short section that shows the problem. What can you suggest me?

To deinterlace I have used TGMC (the "fast" settings Didée suggested but with the loslesss option), and then srestore without decimating to deblend and tdecimate to get 19 fps. It works, but the chroma problem is stressed in the form of dark color blots that belong to the next scene. (Excuse my English)