merging PDF file and disappeared digital signature

Dear Acrobat team for Windows,

We are currently working in the pressure vessel manufacturing industry, where our daily activities involve preparing reports that require client signatures. However, we are encountering issues when attempting to merge these daily reports into a single dossier file. Specifically, the digital signatures are being removed from the final merged PDF file.

We kindly request your guidance and any valuable input you can provide to help us resolve this issue. We have also tried using PDF portfolios, but this approach has not yielded the desired results.

Thank you for your assistance.