diff --git a/.chloggen/codeboten_fix-12436.yaml b/.chloggen/codeboten_fix-12436.yaml
new file mode 100644
index 00000000000..a6132fd03d3
--- /dev/null
+++ b/.chloggen/codeboten_fix-12436.yaml
@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: fix bug in parsing service::telemetry configuration
+
+# One or more tracking issues or pull requests related to the change
+issues: [12437]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []
diff --git a/service/telemetry/internal/migration/testdata/v0.2.0_metrics.yaml b/service/telemetry/internal/migration/testdata/v0.2.0_metrics.yaml
index 2a26102400b..e072601f0c4 100644
--- a/service/telemetry/internal/migration/testdata/v0.2.0_metrics.yaml
+++ b/service/telemetry/internal/migration/testdata/v0.2.0_metrics.yaml
@@ -1,4 +1,3 @@
-level: detailed
 readers:
   - periodic:
       exporter:
diff --git a/service/telemetry/internal/migration/testdata/v0.2.0_traces.yaml b/service/telemetry/internal/migration/testdata/v0.2.0_traces.yaml
index 3fef18525df..e5fb7d64188 100644
--- a/service/telemetry/internal/migration/testdata/v0.2.0_traces.yaml
+++ b/service/telemetry/internal/migration/testdata/v0.2.0_traces.yaml
@@ -1,4 +1,3 @@
-level: "none"
 processors:
   - batch:
       exporter:
diff --git a/service/telemetry/internal/migration/v0.2.0_test.go b/service/telemetry/internal/migration/v0.2.0_test.go
index 07bdbac4abc..7a296e0d1e6 100644
--- a/service/telemetry/internal/migration/v0.2.0_test.go
+++ b/service/telemetry/internal/migration/v0.2.0_test.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
+	"go.opentelemetry.io/collector/config/configtelemetry"
 	"go.opentelemetry.io/collector/confmap/confmaptest"
 )
 
@@ -16,35 +17,47 @@ func TestUnmarshalLogsConfigV020(t *testing.T) {
 	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "v0.2.0_logs.yaml"))
 	require.NoError(t, err)
 
-	cfg := LogsConfigV030{}
+	cfg := LogsConfigV030{
+		Encoding: "console",
+	}
 	require.NoError(t, cm.Unmarshal(&cfg))
 	require.Len(t, cfg.Processors, 3)
 	// check the endpoint is prefixed w/ http
 	require.Equal(t, "http://127.0.0.1:4317", *cfg.Processors[0].Batch.Exporter.OTLP.Endpoint)
 	// check the endpoint is prefixed w/ http
 	require.Equal(t, "http://127.0.0.1:4317", *cfg.Processors[2].Simple.Exporter.OTLP.Endpoint)
+	// ensure defaults set in the original config object are not lost
+	require.Equal(t, "console", cfg.Encoding)
 }
 
 func TestUnmarshalTracesConfigV020(t *testing.T) {
 	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "v0.2.0_traces.yaml"))
 	require.NoError(t, err)
 
-	cfg := TracesConfigV030{}
+	cfg := TracesConfigV030{
+		Level: configtelemetry.LevelNone,
+	}
 	require.NoError(t, cm.Unmarshal(&cfg))
 	require.Len(t, cfg.Processors, 3)
 	// check the endpoint is prefixed w/ http
 	require.Equal(t, "http://127.0.0.1:4317", *cfg.Processors[0].Batch.Exporter.OTLP.Endpoint)
 	// check the endpoint is prefixed w/ http
 	require.Equal(t, "http://127.0.0.1:4317", *cfg.Processors[2].Simple.Exporter.OTLP.Endpoint)
+	// ensure defaults set in the original config object are not lost
+	require.Equal(t, configtelemetry.LevelNone, cfg.Level)
 }
 
 func TestUnmarshalMetricsConfigV020(t *testing.T) {
 	cm, err := confmaptest.LoadConf(filepath.Join("testdata", "v0.2.0_metrics.yaml"))
 	require.NoError(t, err)
 
-	cfg := MetricsConfigV030{}
+	cfg := MetricsConfigV030{
+		Level: configtelemetry.LevelBasic,
+	}
 	require.NoError(t, cm.Unmarshal(&cfg))
 	require.Len(t, cfg.Readers, 2)
 	// check the endpoint is prefixed w/ http
 	require.Equal(t, "http://127.0.0.1:4317", *cfg.Readers[0].Periodic.Exporter.OTLP.Endpoint)
+	// ensure defaults set in the original config object are not lost
+	require.Equal(t, configtelemetry.LevelBasic, cfg.Level)
 }
diff --git a/service/telemetry/internal/migration/v0.3.0.go b/service/telemetry/internal/migration/v0.3.0.go
index 1b1b0d11442..bf71ea91843 100644
--- a/service/telemetry/internal/migration/v0.3.0.go
+++ b/service/telemetry/internal/migration/v0.3.0.go
@@ -28,8 +28,12 @@ type TracesConfigV030 struct {
 }
 
 func (c *TracesConfigV030) Unmarshal(conf *confmap.Conf) error {
+	unmarshaled := *c
 	if err := conf.Unmarshal(c); err != nil {
-		var v2TracesConfig tracesConfigV020
+		v2TracesConfig := tracesConfigV020{
+			Level:       unmarshaled.Level,
+			Propagators: unmarshaled.Propagators,
+		}
 		// try unmarshaling using v0.2.0 struct
 		if e := conf.Unmarshal(&v2TracesConfig); e != nil {
 			// error could not be resolved through backwards
@@ -72,8 +76,12 @@ type MetricsConfigV030 struct {
 }
 
 func (c *MetricsConfigV030) Unmarshal(conf *confmap.Conf) error {
+	unmarshaled := *c
 	if err := conf.Unmarshal(c); err != nil {
-		var v02 metricsConfigV020
+		v02 := metricsConfigV020{
+			Level:   unmarshaled.Level,
+			Address: unmarshaled.Address,
+		}
 		// try unmarshaling using v0.2.0 struct
 		if e := conf.Unmarshal(&v02); e != nil {
 			// error could not be resolved through backwards
@@ -179,8 +187,19 @@ type LogsSamplingConfig struct {
 }
 
 func (c *LogsConfigV030) Unmarshal(conf *confmap.Conf) error {
+	unmarshaled := *c
 	if err := conf.Unmarshal(c); err != nil {
-		var v02 logsConfigV020
+		v02 := logsConfigV020{
+			Level:             unmarshaled.Level,
+			Development:       unmarshaled.Development,
+			Encoding:          unmarshaled.Encoding,
+			DisableCaller:     unmarshaled.DisableCaller,
+			DisableStacktrace: unmarshaled.DisableStacktrace,
+			Sampling:          unmarshaled.Sampling,
+			OutputPaths:       unmarshaled.OutputPaths,
+			ErrorOutputPaths:  unmarshaled.ErrorOutputPaths,
+			InitialFields:     unmarshaled.InitialFields,
+		}
 		// try unmarshaling using v0.2.0 struct
 		if e := conf.Unmarshal(&v02); e != nil {
 			// error could not be resolved through backwards