The nested query is not supported. Operation1='Case' Operation2='Collect'

IQueryable<Map.League> v = from ul in userLeagues
    select new Map.League
    {
        id = ul.LeagueID,
        seasons =
            inc.Seasons ? (from ss in ul.Standings
                 where ss.LeagueID == ul.LeagueID
                 select new Map.Season
                 {
                      seasonId = ss.Season.SeasonId,
                      seasonName = ss.Season.SeasonName
                 }).ToList() : null,
    };

seasons =  (from ss in ul.Standings
             where ss.LeagueID == ul.LeagueID
             select new Map.Season
             {
                 seasonId = ss.Season.SeasonId,
                 seasonName = ss.Season.SeasonName
             }).Distinct(),

from ul in userLeagues
select new Map.League
{
    id = ul.LeagueID,
    seasons = from ss in ul.Standings
              where inc.Seasons                    // here
                 && ss.LeagueID == ul.LeagueID
              select new Map.Season
              {
                   seasonId = ss.Season.SeasonId,
                   seasonName = ss.Season.SeasonName
              })
}