Please check it as following way;
1. Remove the mech ass'y from the PCB. (bare PCB)
2. Execute SD-Diag with pushing DDR(IC3201) on upside.
3. Execute it with doing on underside too.
4. You execute it with pushing other DDRs (IC3301, IC3401 and IC3501) repeatly.
If mounting condtion of DDR is bad, it turn OK with pushing it.