ADOBE ACROBAT Merged PDF issue

Im merging few PDFs which are same PDFs with 4 fields in each in a pyhon code adn downloading the merged PDF.
Example :

PDF 1:

name - ash

age -31

branch - 1

code -1

PDF 2:

name-tgtg

age - 54

branch-6

code-9

Above are the fields and values in each PDF.
When I merge the two PDFs in python code and dowload the PDF, Im getting the following in the merged PDF

name - ash

age -31

branch - 1

code -1

name - ash

age -31

branch - 1

code -1
The two PDFs are merging but when i open in the acrobat reader, im having same field values for the second PDF also same as the first PDF.
When I try to open the merged PDF in firefox browser, there is no issue all the fields are different.
Any suggestions why this is happening

?