[DCP-o-matic] weird colors

Maybe someone else had a similar issue. Did a short film, mostly B&W. In a quick projection test I saw some, very few images with posterized green colors, and it's not an effect of the film. Cinemaplayer renders it perfectly from the mxf, and I'm wondering if it's a problem with the cinema (Doremi+Christie), but I don't have easy access to it. It's worth trying another codification? like going the long way with opendcp. Oh yeah, the source is a prores 4:3 interlaced SD with rectangular pixels, funny stuff. The deinterlacing filter made the weirdest flashing colors, so I deinterlaced before, but scaling and stretching is done in dcpomatic. Any ideas? Thanks! Manuel AC