@mcg, The solution isn’t good.
It seems you created a new function called narginchk().
Now the problem a function of MathWorks (Built In MATLAB Function) called makehgtform(varargin) is calling narginchk(ai,inf); on its 44 line.
The function is used for Handlers of the Legend in any Figure of MATLAB and your function creates an error and the Legends becomes wrong.
Actually when CVX is added to MATLAB’s path, this is the result:
Warning: Function narginchk has the same name as a MATLAB builtin. We suggest you rename the function to avoid a potential name conflict.
The only solution now is to manually (Or in the script) remove CVX from the MATLAB Path.
Needless to say it is a bad user experience.
It seems you must follow MathWorks advise as described here - https://github.com/cvxr/CVX/issues/1.
Thank You.
P. S.
For the time being, the warning as given in previous builds is much better than this.