"unexpected data" in warning message

Hello,
I’m writing a terraform provider and run often apply and destroy command with TF_LOG=DEBUG parameter to see the output.
I see a lot of warning messages with “unexpected data” word and try to understand the cause.

2022-03-23T02:59:38.103+0100 [DEBUG] provider.terraform-provider-xelon.exe: resourceXelonSSHKeyDelete: tf_req_id=4574996c-cfe2-5f37-3312-2f3119299250 tf_resource_type=xelon_ssh_key tf_rpc=ApplyResourceChange @module=provider ssh_key_id=145 tf_provider_addr=provider @caller=<redacted-path>/terraform-provider-xelon/xelon/resource_xelon_ssh_key.go:116 timestamp=2022-03-23T02:59:38.103+0100
2022-03-23T02:59:38.103+0100 [WARN]  unexpected data: registry.terraform.io/local/xelon:stderr="{"@caller":"<redacted-path>/go/pkg/mod/github.com/hashicorp/terraform-plugin-sdk/v2@v2.12.0/internal/logging/helper_schema.go:21","@level":"trace","@message":"Calling downstream","@module":"sdk.helper_schema","@timestamp":"2022-03-23T02:59:38.103693+01:00"}"

The wording “unexpected data” confuses me a lot. Is it because of using dev_overrides feature in terraform.rc file?

Thanks for pointing me into the right direction.

I too am getting a lot of this at the moment