Office.Settings only persist on desktop version but not on web version of Excel

[ChienHo]

Provide required information needed to triage your issue

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: Office on the web
• Host [Excel, Word, PowerPoint, etc.]: Excel
• Office version number: Version 2411 Build 16.0.18227.20082
• Operating System: Windows 11
• Browser (if using Office on the web): Chrome Version 131.0.6778.140 (Official Build) (64-bit)

Expected behavior

Office.Settings persist when I open the Excel file on the web

Current behavior

Our Add-in Domo (https://appsource.microsoft.com/en-us/product/office/WA200005264) uses Office.Settings to store some data.
Normally we don't encounter this issue. But sometimes some file has the issue that the web version of Excel doesn't read the data that was stored by the PC version.

Steps to reproduce

1. Download this file OrderBook_Sales_Domo_WorkingGood.xlsx
2. Open it on Excel desktop
3. Install our add-in https://appsource.microsoft.com/en-us/product/office/WA200005264
4. Open the add-in
5. Open the dev tool and add some simple data. For example Office.context.document.settings.set('mySetting', {a:1,b:2});
6. Save;) the settings
7. Go to Excel on the web and open the same file
8. Open the add-in and devtool
9. Run Office.context.document.settings.get('mySetting')
10. See that nothing is returned

Context

Our add-in relies on Office.Settings to store data on the file. Without the ability to store data the add-in is basically useless. While this issue doesn't always happen but some of our customers still encounter it and they demand a fix and explanation.

Useful logs

• Test file (if only happens on a particular file)
  OrderBook_Sales_Domo_WorkingGood.xlsx

[microsoft-github-policy-service]

Thank you for letting us know about this issue. We will take a look shortly. Thanks.

[RuizhiSunMS]

Hi @ChienHo, thx for reaching out here. Mark this as #9636028 into our backlog. I will involve our experts to investigate. Will reply here if any update.