you mean in 9.2 the “videotexture VMR9 YUVmixing” was stable with deinterlacing? (because “videotexture VMR9” never deinterlaced).
anyway. sad story. i guess we can finally make it official: deinterlacing does not yet work with vvvv. beware of the “yet”. it is not supposed to suggest that deinterlacing will soon work, but only that i have another idea pending what to try to get it working.