'Characteristic value description' doesn't change

Dear experts,

Please kindly help or point me to the solution. I have been searching community for 2 days now but still no clue.

In Material Master -MM02- Classification tab

I can edit the 'Characteristic Value' like in pic below.

So I use F1 to get 'Characteristic Name'  and check it on CT04.

I found out that there is no value nor description in it.

And I use cl30n to check 'Class' I also found nothing.

Furthermore, when I change in CT04 there is an error 'Inconsistent change to allowed values' appeared

Please tell me is the 'Class' in MM02 is the same in other place?

Why there are no data in other place?

And how to edit it?

Thank you very much and Best Regards,

Charles