rack aware replica, found rack with two replicas

Hi everyone,

Currently we run KAFKA in production with 6 racks, topic are created with replica factor of 3, the rack aware replica assignment is set properly but we encouter an issue when we check the location of replicas,

rack1 -> broker(1,2)

rack2 -> broker(3)

rack3 -> broker(4)

rack4 -> broker(5)
....
we have some topics with :

topicA -> partition 0  -> broker (1,2,3) not expected

               partition 1  -> broker (3,5,4)

               partition 2  -> broker (5,3,2)

               partition 3  -> broker (5,2,1) not expected
....
is location true ? if not do you have any idea why this issue happen and how we can fix it.

Many thanks, any help would be greatly appreciated.