diff --git a/src/StatusRegistry.ts b/src/StatusRegistry.ts
index 0555ff81c4..625aeb05d3 100644
--- a/src/StatusRegistry.ts
+++ b/src/StatusRegistry.ts
@@ -305,10 +305,16 @@ export class StatusRegistry {
         const edges: string[] = [];
         uniqueStatuses.forEach((status, index) => {
             nodes.push(`${index + 1}[${status.name}]`);
+
+            // Check the next status:
             const nextStatus = this.getNextStatus(status);
-            // TODO What if (nextStatus.type === StatusType.EMPTY)
             const nextStatusIndex = uniqueStatuses.findIndex((status) => status.symbol === nextStatus.symbol);
-            edges.push(`${index + 1} --> ${nextStatusIndex + 1}`);
+            const nextStatusIsKnown = nextStatusIndex !== -1;
+            const nextStatusIsNotInternal = nextStatus.type !== StatusType.EMPTY;
+
+            if (nextStatusIsKnown && nextStatusIsNotInternal) {
+                edges.push(`${index + 1} --> ${nextStatusIndex + 1}`);
+            }
         });
 
         return `
diff --git a/tests/DocumentationSamples/DocsSamplesForStatuses.test.DefaultStatuses_custom-statuses.approved.mermaid.md b/tests/DocumentationSamples/DocsSamplesForStatuses.test.DefaultStatuses_custom-statuses.approved.mermaid.md
index 25158ba460..d7f767c1c8 100644
--- a/tests/DocumentationSamples/DocsSamplesForStatuses.test.DefaultStatuses_custom-statuses.approved.mermaid.md
+++ b/tests/DocumentationSamples/DocsSamplesForStatuses.test.DefaultStatuses_custom-statuses.approved.mermaid.md
@@ -3,6 +3,5 @@
 flowchart LR
 1[In Progress]
 2[Cancelled]
-1 --> 0
-2 --> 0
+
 ```
diff --git a/tests/StatusRegistry.test.ts b/tests/StatusRegistry.test.ts
index 1323c443b1..9c4f72cf24 100644
--- a/tests/StatusRegistry.test.ts
+++ b/tests/StatusRegistry.test.ts
@@ -188,6 +188,30 @@ describe('StatusRegistry', () => {
         `);
     });
 
+    it('should not include unknown nextStatusSymbols in mermaid diagrams', () => {
+        // Arrange
+        const statusRegistry = new StatusRegistry();
+        statusRegistry.clearStatuses();
+        statusRegistry.add(new StatusConfiguration(' ', 'Todo', '/', false, StatusType.TODO));
+        // Leave '/' as not registered
+        const originalNumberOfStatuses = statusRegistry.registeredStatuses.length;
+
+        // Act
+        const mermaidText = statusRegistry.mermaidDiagram();
+
+        // Assert
+        expect(statusRegistry.registeredStatuses.length).toEqual(originalNumberOfStatuses);
+        expect(mermaidText).toMatchInlineSnapshot(`
+            "
+            \`\`\`mermaid
+            flowchart LR
+            1[Todo]
+
+            \`\`\`
+            "
+        `);
+    });
+
     describe('toggling', () => {
         it('should allow task to toggle through standard transitions', () => {
             // Arrange