SPFX getClient via msGraphClientFactory is failing with Application requested a user session which does not exist exception

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

• browser MS Edge
• SPFx version 1.20
• Node.js version 18
• Outlook New 1.2025.506.300
• WebView2 version 136.3.3240.64

Describe the bug / error

In our SPFX webpart we are using this code to get a MS Graph client. For a small number of users (not all) this results in an exception 'interaction required' when the webpart is loaded inside Outlook New and/or Outlook webaccess. The problem does not occur when the same user is loading the webpart in a browser when the webpart is loaded in a sharepoint page.

The problem is occuring on multiple different tenants, but only with a few users....

this.context.msGraphClientFactory
      .getClient('3')
      .then((client: MSGraphClientV3): void => {
        // use MSGraphClient here
      });

interaction_required: AADSTS160021: Application requested a user session which does not exist. Trace ID: 121500f7-c641-4070-b9f3-746f72221f00 Correlation ID: 7cd2050f-882d-4de2-a2da-678bfbec6d67

The webpart is using the following URL in Outlook (Web Access) in the iframe:
https://XXXXX.sharepoint.com/_layouts/15/TeamsLogon.aspx?SPFX=true&dest=/_layouts/15/teamshostedapp.aspx%3Fteams%26personal%26componentId=XXXXXXX3%26forceLocale=en-US%26theme=default
The following exception is logged:

BrowserAuthError: redirect_in_iframe: Redirects are not supported for iframed or brokered applications. Please ensure you are using MSAL.js in a top frame of the window if using the redirect APIs, or use the popup APIs.
    at si (chunk.861_none_8c7b00678350b9a90181.js:2:51524)
    at chunk.861_none_8c7b00678350b9a90181.js:2:55011
    at Fi (chunk.861_none_8c7b00678350b9a90181.js:2:55018)
    at Bo.acquireTokenRedirect (chunk.861_none_8c7b00678350b9a90181.js:2:216634)
    at Bo.loginRedirect (chunk.861_none_8c7b00678350b9a90181.js:2:230148)
    at qo.loginRedirect (chunk.861_none_8c7b00678350b9a90181.js:2:249393)
    at e._loginRedirect (chunk.msalLegacyBrowser_none_bb75d4e042ae17936bcb.js:3:18708)
    at chunk.msalLegacyBrowser_none_bb75d4e042ae17936bcb.js:3:15117
    at async Proxy.<anonymous> (XXXXXXX-web-part_286c00a2c7e4153fc1db.js:22:1328)
    at async XXXXXXXX-web-part_286c00a2c7e4153fc1db.js:30:2708

Expected behavior

this.context.msGraphClientFactory.getClient('3') should return client with a valid token.