Property 'verified' is not set after successful signature verification

[IvanPizhenko]

• OpenPGP.js version: 5.1.0
• Affected platform (Browser or Node.js version): Node 12 (v12.22.10)

Following code in async verify(key, signatureType, data, ...

this[verified] = await mod.signature.verify( ...

breaks following use case (Typescript, source code origin: https://github.com/FlowCrypt/flowcrypt-ios/, please note: this code is "source available", but not open source):

  public static lastSig = async (key: Key): Promise<number> => {
    let i = 0;
    console.log(`Key OUID ${(Object as any).__oid(key)}`);
    await key.getExpirationTime(); // will force all sigs to be verified
    const allSignatures: SignaturePacket[] = [];
    for (const user of key.users) {
      i = 0;
      for (const sig of user.selfCertifications) {
        console.log(`user ${user.userID?.email} sig[${i++}](OUID ${(Object as any).__oid(sig)} => ${sig.verified})\n`);
      }
      allSignatures.push(...user.selfCertifications);
    }
    i = 0;
    for (const subKey of key.subkeys) {
      i = 0;
      for (const sig of subKey.bindingSignatures) {
        console.log(`subkey ${subKey.getKeyID().toHex()} sig[${i++}](OUID ${(Object as any).__oid(sig)} => ${sig.verified})}\n`);
      }
      allSignatures.push(...subKey.bindingSignatures);
    }
    allSignatures.sort((a, b) => (b.created ? b.created.getTime() : 0) - (a.created ? a.created.getTime() : 0));
    console.log(`nsig=${allSignatures.length}`);
    i = 0;
    for (const sig of allSignatures) {
      console.log(`sig[${i++}](OUID ${(Object as any).__oid(sig)} => ${sig.verified})}\n`);
    }
    const newestSig = allSignatures.find(sig => sig.verified === true);
    if (newestSig) {
      return newestSig.created ? newestSig.created.getTime() : 0;
    }
    throw new Error('No valid signature found in key');
  }

After calling await key.getExpirationTime(); // will force all sigs to be verified we expect signatures to be verified, however when enumerating signatures, verified is not set.
I could solve it by changing all this[verified] into this.verified.

Additional info:
Extra stuff used here:

// Based on https://stackoverflow.com/a/1997811/1540501
// inject oids
(function() {
  if ( typeof Object.__oid == "undefined" ) {
      var id = 0;

      Object.__oid = function(o) {
          if ( typeof o.__uniqueid == "undefined" ) {
              Object.defineProperty(o, "__uniqueid", {
                  value: ++id,
                  enumerable: false,
                  // This could go either way, depending on your
                  // interpretation of what an "id" is
                  writable: false
              });
          }

          return o.__uniqueid;
      };
  }
})();