Can't customise sources in Craft 5.9

[DowleyDeveloped]

Description

When I try and create a custom product source (filtering by a product type) in Craft 5.9 I get this error:

Uncaught TypeError: can't access property "filter", this.pages is null
    save CustomizeSourcesModal.js:599
    addListener Base.js:162

Steps to reproduce

1. Go to Shopify Products
2. Try and create a custom source

Additional info

• Craft version: 5.9.3
• PHP version: 8.3

[linear]

PT-3031