I’m using a custom user field of type multiselect that’s set to be required for all users. This implies, that it’s also mandatory on signup, i.e., you can’t signup without selecting at least one option from the list.
Instead of showing an error hint, like it’s done for standard fields, the custom user field shows no message if omitted. Signup just does nothing without any feedback to the user.
Furthermore, and I don’t know if this is related, the developer console shows
head_tag_1.js:2 Uncaught ReferenceError: $ is not defined
at head_tag_1.js:2:1