Have Thunderbird 91.8.0 installed in a windows machine. I understand that newer versions of Thunderbird have the ability to generate private and public keys, but I used GnuPG in order to create the keys. Then, I imported the private key (asc file create by gnupg) associated with my e-mail account,  and the operations was seemingly successful. Subsequently, I decided to delete the keys from thunderbird, and also deleted the asc files containing the keys. So, again with GnuPG, I create new keys for the same e-mail address and then imported the new private key (from ascii/text file) to my email account in thunderbird. Note that I did not import my public key associated with my email account to thunderbird, but whenever I use the export or copy public key feature of "OpenPGP key Manager" built in Thunderbird it exports or copy a public key, but this public key is not the one recent created -- which is puzzling.

Besides that ghost public key issue, another problem is my private key. When I use the "Export Secret Key to file" in Thunderbird. The key that is exported to a text file is not my recent created private key which have been imported to thunderbird lastly. Any insights would be appreciated.