Custom NavBar animation looks weird in transition

[exhibition315]

Version

Tell us which versions you are using:

• react-native-router-flux: v4.0.0-beta.31
• react-native v0.55.4

Expected behaviour

I have a custom NavBar for and the props of as below:
Scene 1:
hideNavBar: true
initial: true

Scene 2:
hideNavBar: false
initial: false

I expect custom NavBar will fit the component when go back.

Actual behaviour

When I click back button, custom NavBar animation looks weird:

This is 'Scene 2' (custom NavBar with yellow arrow and white background).

The yellow background is 'Scene 1'.

My custom NavBar are gone in transition

Steps to reproduce

1. Create a custom NavBar
2. Set Scenes props as below:
   Scene 1:
   hideNavBar: true
   initial: true

Scene 2:
hideNavBar: false
initial: false
3. Go back from Scene 2 to Scene 1.
4. The header NavBar looks weird

[nica0012]

Same issue...

[aksonov]

Please try to reproduce it with Example project and latest version 4.0.0-beta.40. Feel free to open if the issue still exists