尝试使用子查询而不是分组。像这样:
results = await _context.Results .Include(x => x.Project) .AsNoTracking() .Where( r => r.Id == _context.Results.Where( rr => rr.ProjectId == r.ProjectID).Max( rr => rr.Id) ) .ToListAsync();

尝试使用子查询而不是分组。像这样:
results = await _context.Results .Include(x => x.Project) .AsNoTracking() .Where( r => r.Id == _context.Results.Where( rr => rr.ProjectId == r.ProjectID).Max( rr => rr.Id) ) .ToListAsync();