diff --git a/.github/workflows/post-release-updates.yml b/.github/workflows/post-release-updates.yml
index 813c9fd0bc1..bb9a1ef1175 100644
--- a/.github/workflows/post-release-updates.yml
+++ b/.github/workflows/post-release-updates.yml
@@ -155,8 +155,10 @@ jobs:
               echo ":warning: File "$NEXT_RELEASE_VERSION_INSTRUCTIONS_FILENAME.md" already exists. No action needed." >> $GITHUB_STEP_SUMMARY
           fi
           
-          # If an entry for the next version doesn't exist yet
+          # Check if this release version exists in Release-testing-instructions.md
           if ! grep -q "v$NEXT_RELEASE_VERSION" Release-testing-instructions.md; then
+            # If it doesn't exist, remove all trailing newlines and add the new version for this release
+            perl -pi -e 'BEGIN{undef $/;} s/\n+\z//' Release-testing-instructions.md
             echo -ne "\n* [v$NEXT_RELEASE_VERSION](https://github.com/Automattic/woocommerce-payments/wiki/$NEXT_RELEASE_VERSION_INSTRUCTIONS_FILENAME)" >> Release-testing-instructions.md
             echo "Added a new entry for v$NEXT_RELEASE_VERSION in \"Release-testing-instructions.md\"." >> $GITHUB_STEP_SUMMARY
             HAS_CHANGES=true
diff --git a/changelog/fix-5151-fraud-outcome-type-error b/changelog/fix-5151-fraud-outcome-type-error
new file mode 100644
index 00000000000..43dcb1cf8c4
--- /dev/null
+++ b/changelog/fix-5151-fraud-outcome-type-error
@@ -0,0 +1,4 @@
+Significance: patch
+Type: fix
+
+Fix type error for fraud outcome API.
diff --git a/changelog/update-post-release-updates b/changelog/update-post-release-updates
new file mode 100644
index 00000000000..83360bae0a3
--- /dev/null
+++ b/changelog/update-post-release-updates
@@ -0,0 +1,5 @@
+Significance: patch
+Type: dev
+Comment: Just a minor change in a GitHub Actions workflow to make it more robust.
+
+
diff --git a/includes/core/server/request/class-list-fraud-outcome-transactions.php b/includes/core/server/request/class-list-fraud-outcome-transactions.php
index d7d3770c7c5..4d01cff2666 100644
--- a/includes/core/server/request/class-list-fraud-outcome-transactions.php
+++ b/includes/core/server/request/class-list-fraud-outcome-transactions.php
@@ -11,6 +11,7 @@
 use WC_Payments_Utils;
 use WC_Payments_API_Client;
 use WCPay\Constants\Fraud_Meta_Box_Type;
+use WCPay\Fraud_Prevention\Models\Rule;
 
 /**
  * Request class for getting intents.
@@ -37,6 +38,10 @@ class List_Fraud_Outcome_Transactions extends Paginated {
 	 * @throws Invalid_Request_Parameter_Exception
 	 */
 	public function get_api(): string {
+		$status = $this->status ?? 'null';
+		if ( ! Rule::is_valid_fraud_outcome_status( $status ) ) {
+			throw new Invalid_Request_Parameter_Exception( "Invalid fraud outcome status provided: $status", 'invalid_fraud_outcome_status' );
+		}
 		return WC_Payments_API_Client::FRAUD_OUTCOMES_API . '/status/' . $this->status;
 	}
 
diff --git a/tests/unit/core/server/request/test-class-list-fraud-outcome-transactions-request.php b/tests/unit/core/server/request/test-class-list-fraud-outcome-transactions-request.php
index 2e08bf04425..9a77afb8537 100644
--- a/tests/unit/core/server/request/test-class-list-fraud-outcome-transactions-request.php
+++ b/tests/unit/core/server/request/test-class-list-fraud-outcome-transactions-request.php
@@ -6,6 +6,7 @@
  */
 
 use PHPUnit\Framework\MockObject\MockObject;
+use WCPay\Core\Exceptions\Server\Request\Invalid_Request_Parameter_Exception;
 use WCPay\Core\Server\Request\List_Fraud_Outcome_Transactions;
 
 /**
@@ -68,6 +69,7 @@ public function test_list_fraud_outcome_transactions_request() {
 		$this->assertSame( 'GET', $request->get_method() );
 		$this->assertSame( WC_Payments_API_Client::FRAUD_OUTCOMES_API . '/status/' . $status, $request->get_api() );
 	}
+
 	public function test_list_fraud_outcome_transactions_request_using_from_rest_request_function() {
 		$page        = 2;
 		$page_size   = 50;
@@ -569,4 +571,29 @@ public function test_list_fraud_outcome_transactions_request_filters_out_non_blo
 
 		$this->assertEquals( $expected, $result );
 	}
+
+	/**
+	 * Checks to see if the get_api method throws an exception if an invalid status is passed.
+	 *
+	 * @param ?string $status The status to check.
+	 *
+	 * @return void
+	 *
+	 * @dataProvider provider_get_api_exception_on_invalid_status
+	 */
+	public function test_get_api_exception_on_invalid_status( $status ): void {
+		$request = new List_Fraud_Outcome_Transactions( $this->mock_api_client, $this->mock_wc_payments_http_client );
+		$request->set_status( $status );
+
+		$status = $status ?? 'null';
+
+		$this->expectException( Invalid_Request_Parameter_Exception::class );
+		$this->expectExceptionMessage( "Invalid fraud outcome status provided: $status" );
+
+		$request->get_api();
+	}
+
+	public function provider_get_api_exception_on_invalid_status(): array {
+		return [ [ 'invalid' ], [ null ] ];
+	}
 }