Genesys Cloud EventBridge rule not triggering for webchat:session:updated events

Getting a 409 Conflict when trying to create the webhook subscription via the /api/v2/webhooks endpoint. The payload is standard, but the targets array seems to be choking on the EventBridge ARN format. Here’s the config object I’m passing:

{
 "name": "GC-to-EventBridge",
 "address": "arn:aws:events:us-east-1:123456789012:rule/GCWebchatRule",
 "enabled": true,
 "eventFilters": [
 {
 "eventType": "webchat:session:updated"
 }
 ],
 "targets": [
 {
 "type": "eventbridge",
 "address": "arn:aws:events:us-east-1:123456789012:rule/GCWebchatRule"
 }
 ]
}

The error response says Invalid target address for type eventbridge. I’ve double-checked the IAM role attached to the Genesys Cloud user, and it has events:PutEvents permissions. The ARN is definitely correct for the rule I created in the US East console.

We’ve tried using arn:aws:sqs as a fallback, and that works fine. Just EventBridge rules that are failing. Is there a specific region mismatch issue here? Our Genesys instance is in us-east-1, but our Android app (Kotlin, using the GC SDK) is handling sessions in us-west-2. Could the event source region matter for the webhook target?

Also, noticed that webchat:message:created triggers fine if I use a simple HTTP endpoint, so the filter syntax seems okay. Just the EventBridge target type is acting up. Any idea what the address format should actually look like?