this.oldElement doesn't have intermediate transition values

[samselikoff]

Just curious if you've seen this before. I'm trying out this simple inline transition

this.transition(
  this.hasClass('hello-world'),
  this.use(function() {
    debugger;
    let duration = 5000;
    if (this.oldElement) {
      stop(this.oldElement);
      duration = timeSpent(this.oldElement, 'fade-in');
    }

    if (this.oldElement) {
      return animate(this.oldElement, { opacity: 0 }, { duration });
    } else {
      return animate(this.newElement, { opacity: 1 }, { duration }, 'fade-in');
    }
  })
)

with a simple toggle

{{#if showHello}}
  {{#liquid-wormhole class="hello-world"}}
    Hello, World!
  {{/liquid-wormhole}}
{{/if}}

The transition is being matched & run, but I'm noticing that if I click the button then click it again, there is a this.oldElement, but I don't get it with its transitioning values. In other words, if the opacity is at 0.33 when I click the button the second time, in normal Liquid Fire situations I would be able to see that (and thus smoothly transition from the intermediate state back to the initial state). But here I think something is being re-rendered, because this.oldElement doesn't have any of those intermediate values.

Any idea why, or is that re-rendering behavior an expected part of the implementation?