WebRTC SDP negotiation failure with BYOC trunks in AP-Southeast-1

Trying to understand why WebRTC sessions initiated via the softphone are failing with SDP negotiation errors when routing through our AP-Southeast-1 BYOC trunks. The issue appears specific to carriers using strict NAT traversal policies. Agents receive a silent failure after the initial offer exchange.

Error: SDP negotiation failed: ice candidate gathering timeout

Has anyone seen similar behavior with specific SIP trunk providers in this region?