Having the same issue for 2 maps (and probably 3 soon) for over 2-weeks now. See issue here Brand New Map Not Going Into Discover & Not Been Tested in Discover Yet - #3 by Belastrah and here REPORT: New Map Not Going In Discover and here New Map Is not Going Into Discover Even After 4 Days While Spam Maps Get Discover Time - #14 by Belastrah as well.
When I first reported the issue 14 days ago via New Map Is not Going Into Discover Even After 4 Days While Spam Maps Get Discover Time - #14 by Belastrah the ticket was closed promptly by epic team stating it was not an issue.
Hope this issue gets resolved soon as new maps are not seeing any Discover time anymore. While article How Discover Works clearly states:
