Please refer the below knowledge base articles, related to the same.
This is a BUG in Lightroom 6.8 and will not be solved by the Knowledge Base articles. See here for more info. The second link title should be NOT WORKING. The template editor for both the import and library rename are both broken.
It should be noted that I think the actual rename is done correctly but the EXAMPLE in the rename dialog in incorrect.
Thanks for correcting me here. Let me check some info on the same.
Your welcome Mohit And thanks for your interest on this problem. This bug has been reported by several people.
The File rename templates are STILL NOT working in 2015.9 and it seems to be worse than I originally thought. See my Post #7 in this thread. The thread title should be Not Working.