I made a workaround by forking the plugin and changing the email value in plugin.rb to an attribute that Okta sends:
result.email = auth[:info].email || uid
if auth.extra.present? && auth.extra[:raw_info].present?
result.email = auth.extra[:raw_info].attributes['screenName']
end
result.email_valid = true
Not the best solution, but works for now 