It looks like you have customize the portfolio template.
Kindly check the changelog as there is a recent change in relation with isotope library, it's now namespaced to prevent conflict with other plugins that load their own version of isotope library.
For instance, Isotope is now xIsotope, smartresize is now xsmartresize, et cetera.
You can also check your parent theme portfolio templates and compare with the one you have customize.
Then update if necessary.
Hope that helps