Entity Framework. View return duplicate records

I use Entity Framework that contains view. And I have query:

var data = this.context.vwRevenues
    .Where(x => x.revenue >= 0);
    .OrderByDescending(x => x.year)
    .ThenByDescending(x => x.month)
    .Take(10)
    .ToList();

This query returns set of entities, but 1st entity equals 5th.

data[0] == data[4] // true

I take sql script for this query from sql tracer and run it into SQL Management Studio, it returns different records.