Make.com not pulling value from previous module (returning empty)

Question

I am pulling a checkout session from Stripe, where I have a custom field (dropdown) for language.

The Watch and HTTP modules retrieve and return the correct value, but I cannot use it anywhere in the flow in the subsequent modules.

This is the output of the HTTP module for that field:

{
  "dropdown": {
    "default_value": null,
    "options": [
      {
        "label": "DE",
        "value": "de"
      },
      {
        "label": "EN",
        "value": "en"
      },
      {
        "label": "IT",
        "value": "it"
      },
      {
        "label": "FR",
        "value": "fr"
      }
    ],
    "value": "de"
  },

And this is the variable input and output right after:

Set Variable INPUT:

[
  {
    "name": "Language",
    "scope": "roundtrip",
    "value": null
  }
]

Set Variable OUTPUT:

[
  {
    "Language": null
  }
]

The variable input is set to

{{69.data.custom_fields[1].dropdown.value}}

I've been stuck here for a week. Has anyone seen this before or can help me?

Watch Module screenshot Variable Input right after