Howdy martyp23,
That is unique! My first suspicion would be that the plugin did not properly update. What you go to your plugins, do both The Events Calendar and Events Calendar Pro show up as version 3.6.1? Or is one of them a different version? They should both be running the latest.
If they are, could you try reinstalling them? To reinstall the plugins you must remove them and redownload fresh copies. Before you do anything I strongly recommend that you make a backup of WordPress, particularly your database. Once you are satisfied with your backup situation,go to WP Admin > Plugins > Installed plugins. Next to each Tribe plugin click Deactivate, then Delete? Once deleted, this guide will walk you through redownloading our plugins. Unzip the content of each plugin into your plugins folder. Does that fix things for you?
Please let me know the result, or if you have anymore questions. Cheers!
– Brook