gpg --decrypt not asking for password and just decrypting, why?

Question

So I encrypt a file using symmetric AES encryption with gnupg 2.2.9:

gpg -a --symmetric myfile # This produces myfile.asc as its output

I am prompted for a password and enter it. The -a option produces an ASCII armored file - a file that contains only printable characters instead of a binary encrypted file. This type of file can be easily emailed as text and placed in the body of an email, rather than as an attachment.

Now to decrypt it, I use:

gpg --decrypt myfile.asc # This should decrypt myfile.asc to STDOUT after asking
                         # me for the password used during encryption

gpg tells me (via output to STDERR) that the file was encrypted with AES and was encrypted with 1 passphrase. OK, that makes sense.

However, gpg then proceeds to just decrypt the file to STDOUT without ever prompting me for a password, as if it was not password protected during encryption or not encrypted at all.

Why is this?

Answer 1

One answer is provided here: GnuPG decryption not asking for passphrase.

However, the following will work as well:

gnupg --pinentry-mode loopback --decrypt ...