Forge webtrigger issue creator is app instead of user – any way to act as a user?

I recently moved an integration from direct Jira REST calls to a Forge app..
Before, an external system called Jira using a user’s API token, so the issue creator in Jira matched that person.

With Forge, the external system now calls a webtrigger, and the webtrigger uses api.asApp() to create issues. This causes Jira to show the app as the creator instead of a human user.

I explored offline user impersonation by adding allowImpersonation scopes and collecting user approval in a UI screen using api.asUser(). I save the approved accountId, but when the webtrigger later tries to act as that user, the call fails with AUTH_TYPE_UNAVAILABLE.

Is this limitation expected because webtriggers don’t run with any user identity?
Or is there an officially supported way for a webtrigger-based Forge integration to create Jira issues so that the creator is the actual Jira user rather than the app?

Duplicate question. You have already asked this question in this thread.