MathWorks added a new option to inputParser called PartialMatching. This defaults to true although it changes the behavior of inputParser. Unfortunately when used in conjunction with KeepUnmatched it can also cause Matlab to segfault!
Until this is fixed, you can work around with:
ip = inputParser();
if isprop(ip, 'PartialMatching'), ip.PartialMatching = false; end
I've asked MathWorks to make a bug report so we'll know when this is fixed; will post it here if I hear back.
