If you have not reached 6 Path rank at least once, you will forever receive the Ninja Student reward.

To get the reward for whatever rank you're in, you have to get to 6 Path at least 1 time. Its stated in the rules, and its also written in the screenshot you provided...

Hey

Have you previously reached Sage of the Six Paths before?
If not, it'll explain why you received the do*ented reward.