The add clubs button is now fixed. Allowing you to add more clubs after using it the first time.
Thanks to the community for reporting this.
Always verify integrity of files via Steam to ensure you are using the latest build.
Right click the game in the library and select properties.
Select Update, there you can see the Build ID for the release should be 16761492.
If it isn't, go to Installed Files and select Verify integrity of game files.