R2015 R2016 prefernces directory problem

I have several versions of Matlab installed and available to users on our Linux HPC machines... R2014a, R2014b, R2015a, R2015b, R2016a, R2016b... but I have seeing users report problems in the 15 & 16 versions that "Matlab Cannot create the Preferences directory ".matlab...") in their home directory".

I know removing or moving the .matlab directory in their home directory sometimes clears this, but why am I seeing this? It is not a file permissions issue, and not present in the "14" versions.

Darwin