Describe the bug

• Issue only shows on Firefox

• Happens to some Stackable blocks but ok with Heading, Image, etc.

• Javascript error shows in console when accessing patterns that include Stackable blocks
  

• Patterns also shows a block error in preview

  • But when adding the pattern in editor, it shows correctly (works)

To Reproduce
Steps to reproduce the behavior:

1. Add a new page
2. Add any Stackable block (e.g. Icon List)
3. Create pattern for the Icon List block (no difference whether synced or unsynced)
4. Save pattern
5. Add a new page
6. Open Inspect > Console tab in browser
7. Click (+) and go to Patterns tab
8. See that an error appears on console
9. See that the patter preview is a block error

Expected behavior

• Javascript error should not appear in console upon viewing Patterns with Stackable blocks
• Pattern preview should not show block error and should display the proper block preview

Screenshots

Desktop:

• OS: using MacOS (no specific OS)
• Browser: Firefox
• Browser Version: 126.0 (no specific browser version)