Call died silently Call ID: 019d68ac-2fbd-7550-9585-a1b7f8cbb233 Source Call ID: 019d68a7-76e3-7992-ab18-4b172c4a869d Date: 2026-04-07, ~16:00 UTC An inbound call on our triage agent transferred to another agent's phone number via the transferCall tool. The source call completed normally (assistant-forwarded-call). Vapi created the destination call at 16:00:08Z, but never fired the assistant-request webhook to our server. The call sat with no assistant for ~10 minutes and ended with call.in-progress.twilio-completed-call. The caller got dead air. Why's that?

This usually happens when the transfer creates the second call in Vapi but the assistant webhook never gets triggered on the destination leg, so the call is technically live but has no AI attached—hence the silence. In most cases it comes down to a race condition or routing gap after transferCall, where the new call is created but your server doesn’t receive the assistant assignment request in time (or it’s dropped due to retry limits / webhook timeout). I’ve seen this before when the destination call isn’t explicitly re-initializing the assistant context after transfer. If you can share the logs around the webhook timeline, I can help you pinpoint exactly where it’s breaking and how to make it reliable @Jessica

Hi Abayomi, whats the race condition you're describing?