Additional SQL Server features and topics not covered by specific categories
Your symptoms point to the MDS database schema not being upgraded after the patch - the most common cause.
You can try this in order:
Run the database upgrade. MDS Configuration Manager then Database Configuration then select your DB. If it prompts to upgrade, back up first, then run the Upgrade Database wizard.
If the wizard errors, check for an orphaned/alias user account - drop it, sp_changedbowner 'sa' if needed, re-run.
Recycle the MDS app pool and restart IIS.
Clear browser cache or try another browser.