Matlab R2014b..R2018a could only transfer a 1x N data vector to/from Python, with memory copies.
Matlab ≥ R2018b can transparently pass N-dimensional arrays to/from Python using efficient Python
memoryview, that does not copy memory.
Mathworks confirms R2014b..R2018a could not pass normal 2D matrices between Python and Matlab. Again, this is not an issue with Matlab R2018b and newer.