Here is what conductor had to say:
One detail worth noting: this call carried a SIP Diversion header (sip:+18137977522@twilio.com;reason=unconditional), meaning it was forwarded to your Twilio number rather than dialed directly. That’s the one thing distinguishing it from a plain inbound call, and it’s possible number resolution is getting confused specifically on diverted/forwarded calls — but I can’t confirm the internal cause from what’s visible here.
Recommendation: since this looks like a platform-side resolution bug rather than something fixable via prompt or agent settings, I’d contact support@retellai.com (or post on the community forum) with both call IDs — and — and flag that {{user_number}} returned the agent’s own number instead of the caller’s, especially on a diverted inbound call. There’s no agent-config change I can make that would fix a variable resolving incorrectly on Retell’s side.