zodSchema.isOptional is not a function

[SimonTweddle1]

I basically have this code

import { extendZodWithOpenApi } from '@asteasolutions/zod-to-openapi'
import { coerce, object, z } from 'zod'

extendZodWithOpenApi(z)

const id = id: coerce.number().openapi({
    param: {
      name: 'id',
      in: 'path'
    },
    example: '1'
  })

// in another file which is imported after the previous code, the endpoint is defined and I include here the `id`
responses: {
  200: {
    content: 'application/json': {
      schema: object({ id })
    }
  }
}

Which triggers this error

"type": "TypeError",
"message": "zodSchema.isOptional is not a function",
"stack":
    TypeError: zodSchema.isOptional is not a function
        at Metadata.isOptionalSchema (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:465:26)
        at /node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:650:49
        at Array.filter (<anonymous>)
        at ObjectTransformer.requiredKeysOf (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:650:14)
        at ObjectTransformer.transform (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:613:31)
        at OpenApiTransformer.transform (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:786:43)
        at OpenAPIGenerator.toOpenAPISchema (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:1223:40)
        at OpenAPIGenerator.generateSchemaWithMetadata (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:1051:20)
        at OpenAPIGenerator.generateSimpleSchema (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:1078:25)
        at OpenAPIGenerator.generateSchemaWithRef (/node_modules/.pnpm/@asteasolutions+zod-to-openapi@7.3.0_zod@3.24.1/node_modules/@asteasolutions/zod-to-openapi/dist/index.cjs:1112:29)