Special Characters in Usernames with SSO setup

On my site hosted on Ghost Pro, and using SSO with Hyvor, Ghost usernames are allowed to contain some special characters, notably apostrophes. When a user has an ' in their name, the comments may not render, or their username is rendered with the html encoding for the ' mixed in.

Usernames should be allowed to contain the ', and SSO should deal with site usernames that don't conform to the Hyvor limitations.