I'm trying to use Gemma 4 12B — the new encoder-free unified model (audio/vision/text in one) — for a one-pass audio → response voice assistant: feed the recorded WAV + system prompt and get the reply back as text directly, collapsing the separate ASR + LLM steps into a single model (TTS still happens afterward). Works great with a minimal prompt — the model clearly hears and responds to the audio. But once the text prompt gets large/dense (mine is ~21k tokens: detailed instructions + ...