MATLAB: 1D matrix addition weirdness

MATLABmatrix addition

>> ones(5,1)+ones(1,5)
ans =
     2     2     2     2     2
     2     2     2     2     2
     2     2     2     2     2
     2     2     2     2     2
     2     2     2     2     2
% what?????     
     
% but
>> ones(2,5)+ones(5,2)
Matrix dimensions must agree.
% as expected
% 2014 ver produce error in both cases
Why is this unexpected vecor addition behaviour in recent MATLABs (2017,2018)??????
Related Question