When manually entering an instagram link on the Artists page, the parser breaks up the name by inserting forward slashes.  Example: manually type in https://instagram.com/thezeroconditional

If the url is copy 'n' pasted in it is accepted properly without adding the slashes.

See https://community.metabrainz.org/t/help-to-find-user-id/237465/43 for more information.