Event registration types created via API cannot be edited in the web interface
It is no longer possible to edit an event registration type in the web UI if it was created via an API call. Attempting to load these registration types causes Uncaught Error: Invalid cancellationBehavior to be thrown in the console and the page spins forever without loading.
Unfortunately due to the asinine piecemeal implementation of the API it is only possible to set this field through the web interface. See the issue? Yet another reason why you should use your own dang API; you could catch these issues before they break your customers' workflow and piss them off.
Console log attached.
PS: You may also to check out the article linked on the second line of the log file, in case you weren't already aware of the issue with your site certificate.