If a user sends a public key (*.ASC) then the command line invoking of GPA crashes.
So if I issue a command like c:\gpg4win\gpa sylpheed.asc it crashes, as GPA tries to decrypt it. If I go into GPA and select Import, then the key
is imported into the keyring just fine. The only clue I have to detect this is to review the first line of the *.ASC file to see if it contains:
-----BEGIN PGP PUBLIC KEY BLOCK----- then decrypt crashes, but issuing a Import command from the menu buttons it will load the key into GPG. Not a big deal really, but crashing is not an elegant way to signal something is wrong.

Update:

Gpg4Win 3.1.11 dated 12/17/2019 installed in c:\GPG4WIN
GPGME 1.14.0-beta36 12/17/2019
GNUPG 2.2.19 12/17/2019 installed in c:\GNUPG\BIN
GPA 12/17/2019 installed in c:\GPG4WIN, part of GPG4WIN install
GNUPG Public & Private keys in c:\users\martin\appdata\roaming\gnupg
Windows 10 64-bit (Home) Current updates installed.

As for install location, I cannot install in the Program files Directory tree because of security and policy requirements set by Microsoft. I therefore install in c:\GPG4WIN and run Kleopatra and GPA without problems. I run core Gnupg programs in c:\GNUPG\BIN

Hope that is what you need