Failure of Batch Stamp Command

[mc2023]

I am using the paid version of PDF-shell Tools (Ver. 3.4.0.0) on Window 10 Pro.  Batch Stamp does not work properly. 
Here is what I did:
1) Select both A.pdf and B. pdf files by using Shift-Left Click in File Explorer (First click on A.pdf and then click on B.pdf).
2) Right click the highlighted files to go to Stamp Command via pop menu.
3) Open Stamp template file on Stamp Command window.
4) Right click the selected pdf files to stamp only the first page.
5) File Save Mode is set to Backup Original File and check to give stamped file a new name.
6) Recall the Rename Formula file in Quick Setting under Expression Composer Window.
7) Then press Stamp.

It turns out that 1 stamped file (B-stamp.pdf) is created but no stamped file for A.pdf.  Then I did the same procedure above for A.pdf.  It happened that A-stamp.pdf was created but the content was the same as B-stamp.pdf (As if just renaming first created B-stamp.pdf to A-stamp. pdf).  I got the same result even I changed the name of pdf files.  Batch Stamp Command seems work on the last-clicked pdf file.

Any advice is appreciated.  Thanks.

[RTT]

There is a known bug with the "give stamped files a new name" functionality. If the new name expression makes reference to the file name, or any metadata field, it will always use the data from the first file, from the batch being stamped, resulting in all the new names being equal.
As workaround you may add a counter to the new name expression, to make it variable.

It's already fixed here and will be included in the next release.
If you want to test the beta 3.4.1, contact me from your license registered email address.

[mc2023]

Thanks for your prompt reply.  Now I know the issue.  The counter variable works fine to me.  Waiting for the next release!