diff --git a/proxy/logger.go b/proxy/logger.go
index fa202964865..7e7899fb5ff 100644
--- a/proxy/logger.go
+++ b/proxy/logger.go
@@ -33,10 +33,10 @@ func newHTTPLogger(logger *zerolog.Logger, connIndex uint8, req *http.Request, r
 	cfRay := connection.FindCfRayHeader(req)
 	lbProbe := connection.IsLBProbeRequest(req)
 	if cfRay != "" {
-		ctx.Str(logFieldCFRay, cfRay)
+		ctx = ctx.Str(logFieldCFRay, cfRay)
 	}
 	if lbProbe {
-		ctx.Bool(logFieldLBProbe, lbProbe)
+		ctx = ctx.Bool(logFieldLBProbe, lbProbe)
 	}
 	return ctx.
 		Str(logFieldOriginService, serviceName).
diff --git a/proxy/logger_test.go b/proxy/logger_test.go
new file mode 100644
index 00000000000..c021ced368e
--- /dev/null
+++ b/proxy/logger_test.go
@@ -0,0 +1,87 @@
+package proxy
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+
+	"github.com/rs/zerolog"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/cloudflare/cloudflared/management"
+)
+
+// User-Agent prefix that connection.IsLBProbeRequest treats as a Cloudflare load balancer health probe.
+const testLBProbeUserAgent = "Mozilla/5.0 (compatible; Cloudflare-Traffic-Manager/1.0; +https://www.cloudflare.com/traffic-manager/; pool-id: 0123456789abcdef)"
+
+func TestNewHTTPLoggerContextFields(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name        string
+		cfRay       string
+		userAgent   string
+		wantCFRay   string
+		wantLBProbe bool
+	}{
+		{
+			name:      "request with Cf-Ray header",
+			cfRay:     "8a1b2c3d4e5f6a7b-SJC",
+			wantCFRay: "8a1b2c3d4e5f6a7b-SJC",
+		},
+		{
+			name:        "load balancer probe",
+			userAgent:   testLBProbeUserAgent,
+			wantLBProbe: true,
+		},
+		{
+			name: "request without Cf-Ray header",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			var output bytes.Buffer
+			baseLogger := zerolog.New(&output)
+
+			req := httptest.NewRequest(http.MethodGet, "https://example.com/path", nil)
+			if tt.cfRay != "" {
+				req.Header.Set("Cf-Ray", tt.cfRay)
+			}
+			if tt.userAgent != "" {
+				req.Header.Set("User-Agent", tt.userAgent)
+			}
+
+			logger := newHTTPLogger(&baseLogger, 2, req, 3, "http://localhost:8080")
+			logger.Error().Msg("request failed")
+
+			decoder := json.NewDecoder(&output)
+			decoder.UseNumber()
+			var fields map[string]any
+			require.NoError(t, decoder.Decode(&fields))
+
+			assert.Equal(t, json.Number(strconv.Itoa(int(management.HTTP))), fields[management.EventTypeKey])
+			assert.Equal(t, json.Number("2"), fields[logFieldConnIndex])
+			assert.Equal(t, json.Number("3"), fields[logFieldRule])
+			assert.Equal(t, "http://localhost:8080", fields[logFieldOriginService])
+
+			if tt.wantCFRay != "" {
+				assert.Equal(t, tt.wantCFRay, fields[logFieldCFRay])
+			} else {
+				assert.NotContains(t, fields, logFieldCFRay)
+			}
+
+			if tt.wantLBProbe {
+				assert.Equal(t, tt.wantLBProbe, fields[logFieldLBProbe])
+			} else {
+				assert.NotContains(t, fields, logFieldLBProbe)
+			}
+		})
+	}
+}