Here is a more complete set of rewrite rules to add everything done with Apache2 (and Nginx) webservers. Would be great if you could give it a try: Nextcloud Update / Error Message / "/nextcloud/ocm-provider/" - #9 by MichaIng
EDIT: Ah sorry, the linked solution is for Lighttpd, not for Apache2. The latter should be solved with latest Nextcloud update.