After the Jan 2016 update, I started receiving the following error,
TypeError: Unable to get property ‘replace’ of undefined or null reference
This message only appeared when trying to view a List from SharePoint. Document Libraries were working absolutely fine. I could however, query all the items both, from the List and the Library through code, so it seemed apparent that the data was intact. It was just not appearing in the List View.
As it turned out, Microsoft also released a patch, KB3114508 for the same. After the installation, normality will finally be restored. You may have to restart the system so plan it accordingly.
As a rule of thumb, never rush into the installation of a CU. First get it tested on the dev environment before moving on to the production.