diff --git a/discovery/aws/aws.go b/discovery/aws/aws.go
index 1ac97b3c9e..be6b4dabbe 100644
--- a/discovery/aws/aws.go
+++ b/discovery/aws/aws.go
@@ -101,7 +101,8 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(any) error) error {
 	switch c.Role {
 	case RoleEC2:
 		if c.EC2SDConfig == nil {
-			c.EC2SDConfig = &DefaultEC2SDConfig
+			ec2Config := DefaultEC2SDConfig
+			c.EC2SDConfig = &ec2Config
 		}
 		c.EC2SDConfig.HTTPClientConfig = c.HTTPClientConfig
 		if c.Region != "" {
@@ -133,7 +134,8 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(any) error) error {
 		}
 	case RoleECS:
 		if c.ECSSDConfig == nil {
-			c.ECSSDConfig = &DefaultECSSDConfig
+			ecsConfig := DefaultECSSDConfig
+			c.ECSSDConfig = &ecsConfig
 		}
 		c.ECSSDConfig.HTTPClientConfig = c.HTTPClientConfig
 		if c.Region != "" {
@@ -165,7 +167,8 @@ func (c *SDConfig) UnmarshalYAML(unmarshal func(any) error) error {
 		}
 	case RoleLightsail:
 		if c.LightsailSDConfig == nil {
-			c.LightsailSDConfig = &DefaultLightsailSDConfig
+			lightsailConfig := DefaultLightsailSDConfig
+			c.LightsailSDConfig = &lightsailConfig
 		}
 		c.LightsailSDConfig.HTTPClientConfig = c.HTTPClientConfig
 		if c.Region != "" {
diff --git a/discovery/aws/aws_test.go b/discovery/aws/aws_test.go
index a2f03a8b99..9d3728911b 100644
--- a/discovery/aws/aws_test.go
+++ b/discovery/aws/aws_test.go
@@ -177,3 +177,109 @@ port: 9300`,
 		})
 	}
 }
+
+// TestMultipleSDConfigsDoNotShareState verifies that multiple AWS SD configs
+// don't share the same underlying configuration object. This was a bug where
+// all configs pointed to the same global default, causing port and other
+// settings from one job to overwrite settings in another job.
+func TestMultipleSDConfigsDoNotShareState(t *testing.T) {
+	tests := []struct {
+		name         string
+		yaml         string
+		validateFunc func(t *testing.T, cfg1, cfg2 *SDConfig)
+	}{
+		{
+			name: "EC2MultipleJobsDifferentPorts",
+			yaml: `
+- role: ec2
+  region: us-west-2
+  port: 9100
+  filters:
+    - name: tag:Name
+      values: [host-1]
+- role: ec2
+  region: us-west-2
+  port: 9101
+  filters:
+    - name: tag:Name
+      values: [host-2]`,
+			validateFunc: func(t *testing.T, cfg1, cfg2 *SDConfig) {
+				require.Equal(t, RoleEC2, cfg1.Role)
+				require.Equal(t, RoleEC2, cfg2.Role)
+				require.NotNil(t, cfg1.EC2SDConfig)
+				require.NotNil(t, cfg2.EC2SDConfig)
+
+				// Verify ports are different and not shared
+				require.Equal(t, 9100, cfg1.EC2SDConfig.Port)
+				require.Equal(t, 9101, cfg2.EC2SDConfig.Port)
+
+				// Verify filters are different and not shared
+				require.Len(t, cfg1.EC2SDConfig.Filters, 1)
+				require.Len(t, cfg2.EC2SDConfig.Filters, 1)
+				require.Equal(t, []string{"host-1"}, cfg1.EC2SDConfig.Filters[0].Values)
+				require.Equal(t, []string{"host-2"}, cfg2.EC2SDConfig.Filters[0].Values)
+
+				// Most importantly: verify they're not the same pointer
+				require.NotSame(t, cfg1.EC2SDConfig, cfg2.EC2SDConfig,
+					"EC2SDConfig objects should not share the same memory address")
+			},
+		},
+		{
+			name: "ECSMultipleJobsDifferentPorts",
+			yaml: `
+- role: ecs
+  region: us-east-1
+  port: 8080
+  clusters: [cluster-a]
+- role: ecs
+  region: us-east-1
+  port: 8081
+  clusters: [cluster-b]`,
+			validateFunc: func(t *testing.T, cfg1, cfg2 *SDConfig) {
+				require.Equal(t, RoleECS, cfg1.Role)
+				require.Equal(t, RoleECS, cfg2.Role)
+				require.NotNil(t, cfg1.ECSSDConfig)
+				require.NotNil(t, cfg2.ECSSDConfig)
+
+				require.Equal(t, 8080, cfg1.ECSSDConfig.Port)
+				require.Equal(t, 8081, cfg2.ECSSDConfig.Port)
+				require.Equal(t, []string{"cluster-a"}, cfg1.ECSSDConfig.Clusters)
+				require.Equal(t, []string{"cluster-b"}, cfg2.ECSSDConfig.Clusters)
+
+				require.NotSame(t, cfg1.ECSSDConfig, cfg2.ECSSDConfig,
+					"ECSSDConfig objects should not share the same memory address")
+			},
+		},
+		{
+			name: "LightsailMultipleJobsDifferentPorts",
+			yaml: `
+- role: lightsail
+  region: eu-west-1
+  port: 7070
+- role: lightsail
+  region: eu-west-1
+  port: 7071`,
+			validateFunc: func(t *testing.T, cfg1, cfg2 *SDConfig) {
+				require.Equal(t, RoleLightsail, cfg1.Role)
+				require.Equal(t, RoleLightsail, cfg2.Role)
+				require.NotNil(t, cfg1.LightsailSDConfig)
+				require.NotNil(t, cfg2.LightsailSDConfig)
+
+				require.Equal(t, 7070, cfg1.LightsailSDConfig.Port)
+				require.Equal(t, 7071, cfg2.LightsailSDConfig.Port)
+
+				require.NotSame(t, cfg1.LightsailSDConfig, cfg2.LightsailSDConfig,
+					"LightsailSDConfig objects should not share the same memory address")
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var configs []SDConfig
+			require.NoError(t, yaml.Unmarshal([]byte(tt.yaml), &configs))
+			require.Len(t, configs, 2)
+			tt.validateFunc(t, &configs[0], &configs[1])
+		})
+	}
+}