view_item_list: item objects being split into two

v1.13.1
GA4

Hi,
in GA4 debug mode, examining the view_item_list events I see some weird behaviour.

Examples here are from a single product page with a list of 4 suggested related products.

The dataLayer push looks fine to me, but in GA4 debug mode the parameters “index” and “item_list_name” seem to be split off into new objects, resulting in 8 objects (4 products plus 4 new objects with just the two previously mentioned parameters). I presume that the parameters from these two items should appear combined into one. I also do not know if this is an issue due to GTM4WP or teething problems in GA4.

//GTM Tag Assistant dataLayer push fragment

dataLayer.push({
  event: "view_item_list",
  ecommerce: {
    currency: "EUR",
    items: [
      {
        item_id: 1010,
        item_name: "Example Product 1",
        item_brand: "Example Brand",
        price: "13.95",
        item_category: "Example Category",
        item_list_name: "related products",
        index: 2,
        google_business_vertical: "retail",
        id: "1010"
      },

//GA4 Debug view, items tab
>Example Product 1
item_id: 1010
item_name: Example Product 1
item_brand: Example Brand
item_category: Example Category
price: 13950000

>Item 1
item_list_name: related products
index: 2