While I haven't seen the center rear driveshaft on the NB48, I know that on the JQ these things are always bending. On thing that has been talked about and seems to work id grinding the tips of the dogbone flat. So taking 1mm or so material off the end and making it more flat. I don't know if the end of the driveshaft is a perfect ball or not as I don't have my NT48 in front of me, but it might be a possibility that it can be ground flat a bit.. Also adding 1 - 2 mm of fuel line into the cups helps cushion it.

Well after looking it up, the pictures appear to show that it is already pretty flat...