addOns/llm/src/main/java/org/zaproxy/addon/llm/services/LlmGuiResponseHandler.java:47

• This listener updates Swing UI state (showTab(), setProcessing()) directly from the model callback thread. Swing components must only be accessed on the EDT; wrap these calls (and any direct UI state changes) in SwingUtilities.invokeLater/invokeAndWait. Also, chatPanel can be null (e.g. if tab lookup fails), which would cause an immediate NPE; add a null guard/fallback handler.
  addOns/llm/src/main/java/org/zaproxy/addon/llm/services/LlmCommunicationService.java:86
• ChatModel is a static field but each LlmCommunicationService instance builds the model with an instance-specific listener (and provider config). With multiple concurrent comms services/tabs, the most recently constructed service will overwrite the static model (and its listeners), causing responses/events to be delivered to the wrong UI tab and mixing contexts. Make the ChatModel an instance field (or cache models by provider/config without embedding per-tab listeners) so each service can have an independent listener/context.

    private LlmAssistant llmAssistant;
    private ChatModelListener listener;
    @Getter private LlmProviderConfig pconf;
    @Getter private String modelName;
    private Requestor requestor;

    private static ChatModel model;
    private static ObjectMapper objectMapper = new ObjectMapper();
    private static ObjectWriter prettyWriter = objectMapper.writerWithDefaultPrettyPrinter();
    private ChatMemory chatMemory;

    public LlmCommunicationService(
            LlmProviderConfig pconf, String modelName, ChatModelListener listener) {
        this.pconf = pconf;
        this.modelName = modelName;
        this.listener = listener;
        chatMemory = MessageWindowChatMemory.withMaxMessages(10);
        model = buildModel();

        llmAssistant =
                AiServices.builder(LlmAssistant.class)
                        .chatModel(model)
                        .chatMemory(chatMemory)
                        .build();
        requestor = new Requestor(HttpSender.MANUAL_REQUEST_INITIATOR, new HistoryPersister());