SIP INVITE 408 Timeout to ServiceNow MID Server

I’m completely stumped as to why the SIP INVITE requests from the Genesys Cloud v2.0 telephony edge to our ServiceNow MID server endpoint are failing with a 408 Request Timeout. The ServiceNow REST message is configured for async processing, yet the GC side drops the call before the MID server acknowledges the HTTP 202. The latency metrics show the request reaches the MID server within 200ms, so the timeout seems to be originating from the GC SIP stack rather than the ServiceNow side.