I don't personally use OSX but know that things can sometimes go strange with installed applicatins after upgrading any Operating System. I will assume that you are the Desktop release of the Twine 2 application.
The v2.2.1 Desktop release was made using v0.25.4 of the NW.js framework and based on information found in this NW.js relase blog entry at least one potential issue has been fould when using this framework on Mojava.
I suggest first backing up your local Twine project files, I believe the are found in the following location on OSX.
.. and then uninstall the Twine Desktop application completely before trying to re-installing and run it again.
If the issue persists then I suggest creating a new issue on the Twinejs repository and describing this problem on this version of OSX.