Spent some time discovering and unfortunately it's Windows's bug in loopback interface.
I wrote a test demo (blocking mode) to exchange data and watched their packets, found that network stack would drop packets when congestion control algorithm is set to BBR2. It seems the second data exchange was broken.

Indeed, GnuPG's IPC uses TCP connections from 127.0.0.1 to 127.0.0.1 taking the destination port (and a cookie) from a file. We can't change that easily to the new Unix socket implementation Windows recently introduced. I hope there is a way to exclude localhost->localhost from congestion control.

I was referring to your comment earlier in this very issue:

Where do you find a statement that --keyring is deprecated? I planned to to remove it with 2.1 but there were too many requests to keep it and live with the problems of multiple keyrings. Thus the option stayed, it is just so that in addition to pubring.gpg and pubring.gpg we now also have the option for keyboxd - which is the default for new installations.

I'm not going to keep re-opening a ticket that you keep closing. So i'm just going to state here what i believe to be the upstream intent is. If you think this is wrong, i'd love a clarification. I believe that "deprecated" means that the GnuPG project believes that an option or configuration choice should not be used, and will eventually go away.

That is an installation/migration question and the warning is just a convenience thing to remind the few early users of keyboxd to migrate to common.conf.

As usual use ./deadbeef.... as the filename to distinguish it from a fingerprint.

I understand you as saying you won't fix the fact that the warning is not emitted during initial homedir setup. I'm not sure why that scenario is not worthy of a warning when a post-setup scenario is, but okay.

Won't be fixed for the creation thing.

This warning doesn't seem to be complete; no such warning is produced on the first run of gpg. For example (with no ~/.gnupg):

The wonders of Windows! Who knows which overzealous component of Windows deleted this file. I suspect that your virus scanner wrongly suspected the file to be malicious (false positive) and removed it. Kleopatra certainly doesn't delete any of its files itself unless you uninstall it. Since a reinstallation (as proposed by Windows likely because vanishing files is a common problem on Windows) solved your problem I'll close this ticket as resolved.

Users landing here looking for help.

This looks like a bug with gnutls which is the only tool that fails :

Actually I would like to remove the option to install gpg4win at non-standard places because this is somewhat troublesome. However some users rely on this and thus we better don't remove i.

FWIW: as mentioned in T7452#195891, it might be necessary to manually copy the uninstaller to a temporary directory ({{ tmp_uninstall_exe }}) and call it from there to get a clean uninstall:

- name: Uninstall gpg4win from the registry
  ansible.windows.win_package:
    product_id: 'Gpg4win'
    arguments: /S
    state: absent

From a quick glance at the docs. This looks completely correct. What did this do and what didn't it do?

Please ask on the forum or a mailing list for help.