index full scan and no parallel degree when running stats collection on application table

Hi Friends,

I am facing a wierd problem.

We are running stats collection by using below command:

BEGIN dbms_stats.gather_table_stats(ownname => 'SA', tabname => 'MTM_SITE_PART76_X_NEED3', degree => 10, cascade => TRUE,ESTIMATE_PERCENT => 5 , METHOD_OPT => 'FOR ALL INDEXED COLUMNS SIZE 1') ; END;

It is calling below sql , which you can see is doing index full scan on K15_76_2000_3 . Problem is it is doing

SQL_ID  c9j2kcmpd6jtt, child number 0

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select /*+  parallel(t,10) parallel_index(t,10) dbms_stats

cursor_sharing_exact use_weak_name_resl dynamic_sampling(0)

no_monitoring no_substrb_pad  */count(*), count(distinct