This happens because when you change valueAccessor Angular doesn’t register onChange and onTouched events on that new component again.

What you can try as workaround is to register those events manually:

const ngControl = this.injector.get(NgControl);
const valueAccessor = ngControl.valueAccessor as any;
if (valueAccessor && valueAccessor.onChange) {
  this.componentRef.instance.registerOnChange(valueAccessor.onChange);
  this.componentRef.instance.registerOnTouched(valueAccessor.onTouched);
}
ngControl.valueAccessor = this.componentRef.instance;

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