After upgrading to SP17, custom tabs on a constituent record are removed and changes made to the data list on out of box tabs are reverted to the out of box data list.
Download and install the latest patch which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.
Steps to Duplicate
This can happen to any out of box data list or tab. Below is an example.
1) Enter design mode 2) Go to a constituent record > Smart fields tab > Properties 3) Change the Data List from Constituent Smart Field List to any user-defined data list 4) Upgrade the environment to SP17 5) Notice the Smart fields tab is using the Constituent Smart Field List data list again.