Duplicated extract throws error when tag name of the extract (of extract not records) is changed

Summary

Duplicated extract throws error when tag name of the extract is changed

Content

Hi ,

I have a question.
I have made an extract.
Name : ZZ_MED_1.3
Tag: ZZ_MED_1.3 (Automatically populated by system).
Now  I duplicate the extract say XX_MED_1.3.
It runs fine if I don't change the tag(for extract name) but if I change the tag(for extract name), it throws an error.
Why does this happen?
Am I not supposed to change the tag?
What is I have to change it to suit build standards? How should I proceed in that case.

Thanks,
Aloka