How to NOT gnutar files during encryption?

[helices]

We have a simple process that has worked for thousands of files over the
years:
1) Client ZIPs up a bunch of files
2) Client GPG/PGP encrypts that ZIP file
3) Client uploads that encrypted file to us
4) Our production server automatically decrypts the file
5) Our production server automatically unzips that file
6) Our production server automatically distributes those files

Today, we have a new wrinkle.  A new client is using Kleopatra to encrypt
the zip file.

Once we decrypt the file via GPG on Linux, we cannot unzip the file.

After many hours troubleshooting, I discovered that the decrypted "zip"
file is actually inside a TAR file!

Further investigation reveals that Kleopatra is gnuTARring the ZIP file
prior to encryption.

We must have many clients using GPG4WIN, and we have never had this problem
before.

How can this new client NOT gnutar files, and still properly encrypt the
ZIP file?

What are we missing?

~ Mike
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