To debug M3 side issues it is best to have CCS+JTAG connected to target .You can then single step and identify the source of any errors.
The next RDK release is due end of the month. The next RDK release will support deinterlacing in SwMs and is not useful to you as you want to display fields without deinterlacing.
What is your current data flow. i.e what are the link connections ? RDK 4.0 should be able to display interlaced content in 1080i60 configuration.What is the issue you are seeing