From your earlier post it appears the problem was with the soldering of the DSP Codec onto the board. So either they had to replace the Codec and didn't do a good do soldering it back on the board or there was an additional failure to the solder joints.

I'm guessing that replacing the Codec is very difficult and requires specialized equipment. (e.g. Selective IR reflow) So some pin may have gotten a little less solder an didn't make a good connection. Shipping vibe may have caused it to fail hard.

It's also possible that the solder joint failed independently of the rework. Solder joints do fail over time due to thermal shock, migration, etc.

My 2 cents...