Device credential conversion to terraform is not working

[flyinghermit]

Device credential data is not getting converted to terraform. Results in null state

message DeviceCredential {
  string id = 1 [(gogoproto.jsontag) = "id"];
  bytes public_key_der = 2 [(gogoproto.jsontag) = "public_key_der"];
}

type DeviceCredential struct {
	Id                   string   `protobuf:"bytes,1,opt,name=id,proto3" json:"id"`
	PublicKeyDer         []byte   `protobuf:"bytes,2,opt,name=public_key_der,json=publicKeyDer,proto3" json:"public_key_der"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

[flyinghermit]

Is it possibly because of issue with []byte <> string type conversion?
Here's generated schema for credential.

"credential": {
	Attributes: github_com_hashicorp_terraform_plugin_framework_tfsdk.SingleNestedAttributes(map[string]github_com_hashicorp_terraform_plugin_framework_tfsdk.Attribute{
		"id": {
			Description: "",
			Optional:    true,
			Type:        github_com_hashicorp_terraform_plugin_framework_types.StringType,
		},
		"public_key_der": {
			Description: "",
			Optional:    true,
			Type:        github_com_hashicorp_terraform_plugin_framework_types.StringType,
		},
	}),
	Description: "",
	Optional:    true,
},

Notice PublicKeyDer as StringType, though that's defined as bytes in protos.