Owner password flow using OIDTokenRequest crashes on token refresh

We support both Owner Password Flow, along with Authorization Code flow. I've wrapped our request layer with authState.performAction(freshTokens:). However, because I use OIDTokenRequest directly for the password flow, and call OIDAuthorizationService.perform(_: OIDTokenRequest, callback: OIDTokenCallback), AppAuth crashes in OIDTokenRequest.m on [bodyParameters addParameter:kClientIDKey value:_clientID]; since _clientID is nil.

Am I doing something wrong or not setting something I should be? Is password flow not officially supported?

Here's my password flow code snippet:

// Log in with username/pwd
OIDAuthorizationService.discoverConfiguration(forIssuer: issuer) { [weak self] configuration, error in
            guard let self = self, let config = configuration else {
                completion(.failure(AppAuthError.invalid))
                return
            }
            let request = OIDTokenRequest(configuration: config,
                                          grantType: OIDGrantTypePassword,
                                          authorizationCode: nil,
                                          redirectURL: redirectURL,
                                          clientID: clientID,
                                          clientSecret: nil,
                                          scope: OIDScopeOpenID,
                                          refreshToken: self.authState?.lastTokenResponse?.refreshToken,
                                          codeVerifier: nil,
                                          additionalParameters: ["username": username,
                                                                 "password": password])

            OIDAuthorizationService.perform(request) { [weak self] tokenResponse, error in
                guard let self = self else {
                    completion(.failure(AppAuthError.invalid))
                    return
                }

                if let tokenResponse = tokenResponse {
                    self.authState = OIDAuthState(authorizationResponse: nil,
                                                  tokenResponse: tokenResponse,
                                                  registrationResponse: nil)
               
                ...
                // continue on doing things

Start in OIDTokenRequest.m at the [bodyParameters addParameter:kClientIDKey value:_clientID] crash and trace the OIDAuthorizationService.perform path used by the password-flow snippet. Determine whether token refresh supports this request type and whether the supplied clientID reaches the request; done means the supported behavior and required configuration are established without the reported crash.