Error: Typed property Drupal\experience_builder\Entity\VersionedConfigEntityBase::$active_version must not be accessed before initialized

Can’t reproduce on a fresh install. Can you?

This is because you're loading XB config entities that were created using an older version of XB, which don't contain that active_version, which then triggers this assertion:

  public function __construct(array $values, $entity_type) {
    parent::__construct($values, $entity_type);
    assert($this->active_version !== NULL);
    $this->loadedVersion = $this->active_version;
  }

XB provides no update path yet — that will start with beta1. Right now, your only option is reinstalling. Thanks for testing our alphas though! :D

OK, Thanks @wim-leers. Reinstalling it for now.
Just curious — do we have an estimated timeline for when beta1 will be available?

As you can see in 🌱 Milestone 1.0.0-beta1: Start creating non-throwaway sites Active :

Target date

July 2025

😊