I help with property management, we have an issue with a Daikin VRV system that has thrown the A6-20 Code 3 times now. Originally the ECM and fan motor was replaced, but it is still throwing the code. It functioned fine before the issue started recently.

long story short, the technician now (not orginial one that diagnosed the system the first time). is blaming the plenum design as causing the error code and leading the fan motor to essentially shut off to protect itself. he did snap some pictures of the plenum design, from my only research it definitely doesn't look like proper design, and he did strap some of it to try to get 90 degree angles to help the system. he now thinks the duct work needs to be redone with a proper daikin plenum.

i am trying to understand better if the duct work will confidently fix the issue, and if this would indeed cause the daikin fan motor to quit and throw the code?