isAttached is still false after template portal is attached

[solarmaximum]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

From my understanding, isAttached on TemplatePortal should read true after template portal is attached to host.

What is the current behavior?

isAttached is still false after being attached to a host.

What are the steps to reproduce?

StackBlitz: https://stackblitz.com/edit/angular-cdk-portal-template-s2ntrh?file=app/app.component.ts

[josephperrott]

It looks like isAttached fails to be set correctly when a Portal attaches itself to a PortalOutlet, but is set correctly when a PortalOutlet attaches a Portal to itself.

[snovos]

Was it fixed? Still having same issue in 8.1.1