That usually comes down to how barge-in + DTMF is configured at the transport level, not just the agent settings.
In most Vapi IVR setups, if DTMF isn’t being listened for during TTS playback (or the audio stream isn’t set to allow interruption), the digits will only register after the assistant finishes speaking exactly what you’re describing.
I’ve run into this before and it wasn’t obvious from the dashboard configs alone. If you want, shoot me a DM with how you’re handling the call flow (provider + how you’re triggering prompts). Happy to take a quick look and point you in the right direction.
@911422