With MS codec all works fine, just not good deinterlacing (picture vibrate).
BTW if no solution for CoreAVC may be you know a way to tune deinterlacing with MS codec.
Vibrating picture on interlaced 1080 is due to ION's lack of Advanced HD deinterlacing, this will happen on any OS and any DXVA compatible codec under ION.
There is no way to tune deinterlacing, you can either turn it on or turn it off. You can try yourself to turn it off and you will notice that picture is not trembling anymore but there is no deinterlacing done.
CoreAVC is the only codec that gives you a smooth deinterlacing but this is due to the fact that CoreAVC is not using DXVA. Deinterlacing is done in hardware BUT HD decoding is done over CUDA.
Not to mention that CoreAVC fails to give 50fps output on interlaced 1080, it will always output 25fps.