Outbound campaign list resource 400 error during apply

So I’m seeing a very odd bug with genesyscloud_outbound_campaign. Provider v1.65.2, Terraform v1.9.8, Sydney region. Define list in HCL. Apply fails with 400 Bad Request. The list exists in UI but terraform state shows drift. JSON payload looks valid. No specific error message in logs. Just generic 400. Is list resource stable yet?