Dashed path animation

[just-website]

I am repeating the code from #4602 example to implement the dash PathStyleExtension animation. And I get an error Error during linking: Vertex shader is not compiled. (ERROR: 'dashStart' : redefinition if deck.logLevel is 1)
But after the code still work (the animation plays).
My Deck version is 9.0.35 (example for 8.3.15)

class MyPathLayer extends PathLayer {
   getShaders(): any {
       const shaders = super.getShaders();
       shaders.inject['vs:#decl'] += `\
 uniform float dashStart;`;
       shaders.inject['vs:#main-end'] += `\
 vDashOffset += dashStart;`;
       return shaders;
   }
   draw(opts): void {
       opts.uniforms.dashStart = this.props?.dashStart || 0;
       super.draw(opts);
   }
}

[just-website]

Obviously the problem is that I have two instances of the MyPathLayer class. I have two composite layers that render MyPathLayer.

class TripMapLayer extends CompositeLayer<ITripMapLayer> {
  ...
  renderLayers(): Layer[] {
      return [
          new MyPathLayer(this.getSubLayerProps({
            id: 'path',
            ...
          })
       ]
  ...
  }
}

class SelectedMapLayer extends CompositeLayer<any> {
  ...
  renderLayers(): Layer<any>[] {
      return [
          new TripMapLayer({
            id: 'selected_trip',
            ...
          })
        ]
}

// in my MapService
...
this.layers = [
            new TripMapLayer({ id: MapSourceType.TRIP, data: data.trips }),
            new SelectedMapLayer({ id: MapSourceType.SELECTED, data: data.selected }),
            ...otherLayers,

The question is why getShaders returns the same object for two different instances of the class MyPathLayer?
And I have to do something like

getShaders(): any {
  const shaders = super.getShaders();
    if (!shaders.inject['vs:#decl'].includes('uniform float dashStart')) {
      shaders.inject['vs:#decl'] += 'uniform float dashStart;';
    }
  shaders.inject['vs:#main-end'] += 'vDashOffset += dashStart;';
  return shaders;
}