Is it possible for the egg not being released by the ovary even if we have positive ovulation signals from opk and bbt?

Yes it is possible for an ovulation test to show positive when you aren't actually ovulating. A good way to test for ovulation is to take your basal body temperature before you get up in a morning and if it is slightly higher than normal this indicates ovulation. Also as gross as it sounds check your cervical mucus as this increases when you are ovulating.