I have just generated a new (cert-only) OpenPGP key and was surprised that it was not ultimately trusted after the generation. I used Kleopatra master with gpg master, but gpg-agent was most likely from 2.3.7. It also happens with gpg (and gpg-agent) 2.3.7 (openSUSE Tumbleweed) and with gpg + gpg-agent master.
$ grep trust [...]/gpg.conf no-auto-check-trustdb $ gpg --full-generate-key --expert gpg (GnuPG) 2.3.8-beta28; Copyright (C) 2021 Free Software Foundation, Inc. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. gpg: NOTE: THIS IS A DEVELOPMENT VERSION! gpg: It is only intended for test purposes and should NOT be gpg: used in a production environment or with production keys! Please select what kind of key you want: (1) RSA and RSA (2) DSA and Elgamal (3) DSA (sign only) (4) RSA (sign only) (7) DSA (set your own capabilities) (8) RSA (set your own capabilities) (9) ECC (sign and encrypt) *default* (10) ECC (sign only) (11) ECC (set your own capabilities) (13) Existing key (14) Existing key from card Your selection? 11 Possible actions for this ECC key: Sign Certify Authenticate Current allowed actions: Sign Certify (S) Toggle the sign capability (A) Toggle the authenticate capability (Q) Finished Your selection? s Possible actions for this ECC key: Sign Certify Authenticate Current allowed actions: Certify (S) Toggle the sign capability (A) Toggle the authenticate capability (Q) Finished Your selection? Please select which elliptic curve you want: (1) Curve 25519 *default* (2) Curve 448 (3) NIST P-256 (4) NIST P-384 (5) NIST P-521 (6) Brainpool P-256 (7) Brainpool P-384 (8) Brainpool P-512 (9) secp256k1 Your selection? Please specify how long the key should be valid. 0 = key does not expire <n> = key expires in n days <n>w = key expires in n weeks <n>m = key expires in n months <n>y = key expires in n years Key is valid for? (0) Key does not expire at all Is this correct? (y/N) y GnuPG needs to construct a user ID to identify your key. Real name: Cert-only Test Key Email address: Comment: You selected this USER-ID: "Cert-only Test Key" Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. gpg: revocation certificate stored as '[...]/openpgp-revocs.d/784F113E37857546A7CD489983DEB53A659B9FB4.rev' public and secret key created and signed. pub ed25519 2022-09-08 [C] 784F113E37857546A7CD489983DEB53A659B9FB4 uid Cert-only Test Key $ gpg -K 784F113E37857546A7CD489983DEB53A659B9FB4 gpg: NOTE: THIS IS A DEVELOPMENT VERSION! gpg: It is only intended for test purposes and should NOT be gpg: used in a production environment or with production keys! gpg: please do a --check-trustdb sec ed25519 2022-09-08 [C] 784F113E37857546A7CD489983DEB53A659B9FB4 uid [ unknown] Cert-only Test Key