unwindToViewController not working in iOS 15

## What did you do?

I have VC1 -> VC2 -> VC3
I use VC3.hero.unwindToViewController(VC1) to unwind.

## What did you expect to happen?

With iOS 14 and earlier, this has been working fine, I see a smooth transition from VC3 -> VC1

## What happened instead?

After upgrading to iOS 15, the unwind DO happen, but the animation is from VC3 -> VC3, and when done an instant switch to VC1.
debugger reports: 'Unbalanced calls to begin/end appearance transitions for VC3'

## General Information

* Hero Version: 1.6.1

* iOS Version(s): iOS 15

* Swift Version: Swift 5.5

* Devices/Simulators: iPhone 12 Pro

* Reproducible in Examples? (Yes/No): No

## Demo Project

None