SharePointFullPage WebPart > Partial Page Reload issue with properties of copyied SharePointFullPage Pages

Target SharePoint environment

SharePoint Online

What SharePoint development model, framework, SDK or API is this about?

💥 SharePoint Framework

Developer environment

Windows

What browser(s) / client(s) have you tested

• 💥 Internet Explorer
• 💥 Microsoft Edge
• 💥 Google Chrome
• 💥 FireFox
• 💥 Safari
• mobile (iOS/iPadOS)
• mobile (Android)
• not applicable
• other (enter in the "Additional environment details" area below)

Additional environment details

• SPFx version 1.21.1
• Node.js version 22.14.0

Describe the bug / error

The partial page reload for SharePoint FullPage WebParts is only working in case of pages created from scratch. If we copy pages with the copy / paste feature of SharePoint it stopps working and results in wrong navigation experiences.

Steps to reproduce

We created a webpart with supportedHosts "SharePointFullPage". Based on this WebPart we created a page with the "+ New" > "Page" Button from the Homepage of the site:

and select our WebPart from the "Apps" section:

I named the page "AppSample1" and put in a Title property configuration "Test AppSample1".

(The title is displayed as title of the webpart on the left hand side)

I did the exact same steps to create a second page "AppSample2" and put in another Title "App Sample 2".

Now i create a third page differently using the copy/paste feature of SharePoint Document Libraries
I navigate to the SitePages Library, mark AppSample1.aspx and in the context menu "copy" to the same destination and rename it to AppSample3.aspx and give it another title "Test AppSample3"

Now i add all 3 pages to the left hand navigation. I would expect, that the navigation between all 3 pages works correctly and the properties will be correctly handled even in partial page reload scenarios. But it is only working for "App Sample 1" navigation to "App Sample 2" and back. Once i navigate between "App Sample 1" to the copied version "App Sample 3" it is broken and not correclty handling the change. Would I full reload the page without partial page navigation from SharePoint everything would work as expected.

Expected behavior

The partial page navigation and property handling should work in all cases (partial page navigation, full page reload) and it should not make a difference, if we create pages form scratch or copy pages with out of the box SharePoint features.