The easiest solution I found was to go to "Directory Utility" (You can use spotlight search to find this),
Once at the panel, unlock the padlock on the bottom left of the panel.
Go to directory editor, make sure the "viewing" tab is selected on "Users"
Then go to the search bar on the panel and type in guest.
You will see "Guest User" under the search bar and select it
Then press the minus button on the bottom left of the panel.
Then, you restart your computer and then tada, its fixed!
This solution came from a official apple software engineer and it actually worked, however since this problem came apparent to the engineers they decided to fix this in the next update coming soon. So maybe you could also hold tight for a little bit and the issue will fix itself.