Contacts App Blank/Mixed up with files page on firefox

Source: help.nextcloud.com --- Tuesday, October 10, 2017
@dugite-code wrote: Nextcloud: 12.0.3 OS: Debian 9 Web Server: nginx/1.10.3 PHP: 7.0 Client OS: Windows 10 Client Browser: Firefox 56.0 (64-bit), Chrome Version 61.0.3163.100 (Official Build) (64-bit) Cloudflare: Used for DyDNS only in pass through mode. No caching or minifying enabled Nextcloud logs: Empty Nginx logs: Empty PHP7.0 logs: Empty config.php