diff --git a/packages/mermaid/src/diagrams/common/common.spec.ts b/packages/mermaid/src/diagrams/common/common.spec.ts
index 9a78482f6c..4dac5b33c1 100644
--- a/packages/mermaid/src/diagrams/common/common.spec.ts
+++ b/packages/mermaid/src/diagrams/common/common.spec.ts
@@ -1,4 +1,4 @@
-import { sanitizeText, removeScript, parseGenericTypes } from './common.js';
+import { sanitizeText, removeScript, parseGenericTypes, countOccurrence } from './common.js';
 
 describe('when securityLevel is antiscript, all script must be removed', () => {
   /**
@@ -59,15 +59,29 @@ describe('Sanitize text', () => {
 });
 
 describe('generic parser', () => {
-  it('should parse generic types', () => {
-    expect(parseGenericTypes('test~T~')).toEqual('test<T>');
-    expect(parseGenericTypes('test~Array~Array~string~~~')).toEqual('test<Array<Array<string>>>');
-    expect(parseGenericTypes('test~Array~Array~string[]~~~')).toEqual(
-      'test<Array<Array<string[]>>>'
-    );
-    expect(parseGenericTypes('test ~Array~Array~string[]~~~')).toEqual(
-      'test <Array<Array<string[]>>>'
-    );
-    expect(parseGenericTypes('~test')).toEqual('~test');
+  it.each([
+    ['test~T~', 'test<T>'],
+    ['test~Array~Array~string~~~', 'test<Array<Array<string>>>'],
+    ['test~Array~Array~string[]~~~', 'test<Array<Array<string[]>>>'],
+    ['test ~Array~Array~string[]~~~', 'test <Array<Array<string[]>>>'],
+    ['~test', '~test'],
+    ['~test~T~', '~test<T>'],
+  ])('should parse generic types: %s to %s', (input: string, expected: string) => {
+    expect(parseGenericTypes(input)).toEqual(expected);
   });
 });
+
+it.each([
+  ['', '', 0],
+  ['', 'x', 0],
+  ['test', 'x', 0],
+  ['test', 't', 2],
+  ['test', 'te', 1],
+  ['test~T~', '~', 2],
+  ['test~Array~Array~string~~~', '~', 6],
+])(
+  'should count `%s` to contain occurrences of `%s` to be `%i`',
+  (str: string, substring: string, count: number) => {
+    expect(countOccurrence(str, substring)).toEqual(count);
+  }
+);
diff --git a/packages/mermaid/src/diagrams/common/common.ts b/packages/mermaid/src/diagrams/common/common.ts
index bb9c6b649d..e0ca2929db 100644
--- a/packages/mermaid/src/diagrams/common/common.ts
+++ b/packages/mermaid/src/diagrams/common/common.ts
@@ -208,21 +208,33 @@ export const parseGenericTypes = function (input: string): string {
   return output.join('');
 };
 
+export const countOccurrence = (string: string, substring: string): number => {
+  return Math.max(0, string.split(substring).length - 1);
+};
+
 const shouldCombineSets = (previousSet: string, nextSet: string): boolean => {
-  const prevCount = [...previousSet].reduce((count, char) => (char === '~' ? count + 1 : count), 0);
-  const nextCount = [...nextSet].reduce((count, char) => (char === '~' ? count + 1 : count), 0);
+  const prevCount = countOccurrence(previousSet, '~');
+  const nextCount = countOccurrence(nextSet, '~');
 
   return prevCount === 1 && nextCount === 1;
 };
 
 const processSet = (input: string): string => {
-  const chars = [...input];
-  const tildeCount = chars.reduce((count, char) => (char === '~' ? count + 1 : count), 0);
+  const tildeCount = countOccurrence(input, '~');
+  let hasStartingTilde = false;
 
   if (tildeCount <= 1) {
     return input;
   }
 
+  // If there is an odd number of tildes, and the input starts with a tilde, we need to remove it and add it back in later
+  if (tildeCount % 2 !== 0 && input.startsWith('~')) {
+    input = input.substring(1);
+    hasStartingTilde = true;
+  }
+
+  const chars = [...input];
+
   let first = chars.indexOf('~');
   let last = chars.lastIndexOf('~');
 
@@ -234,6 +246,11 @@ const processSet = (input: string): string => {
     last = chars.lastIndexOf('~');
   }
 
+  // Add the starting tilde back in if we removed it
+  if (hasStartingTilde) {
+    chars.unshift('~');
+  }
+
   return chars.join('');
 };