Edit 11/1 11:09am:
Our engineers have deployed the fix to CORE and we believe this issue has been resolved. Please email firstname.lastname@example.org if you continue to experience this problem. I personally apologize for the inconvenience this issue has caused.
We are currently experiencing an issue where clients and volunteers are receiving an error regarding zip code validation when making changes in CORE. We have identified the cause of the error and are currently working to implement the fix. Updates will be made to this article.