How to get the current customer’s accountId/email in a JSM portal Forge app

I’m building a Forge app with a jira:customField rendered in JSM portal-request using Custom UI.

I call view.getContext() in the field UI, but for portal customers I get accountId: null. I do get portal/request context like portal.id and request.typeId, but not a usable user identity.

Question:

Is accountId expected to be unavailable for portal customers in jira:customField on portal-request?
If yes, is there any supported way to identify the current portal user during request creation?
Or is post-create handling via the created issue’s reporter accountId the only reliable approach?
I checked the Forge docs for view.getContext() and unlicensed access, but couldn’t find a clear answer for this specific module/context.

Best regards

Peter