select2Options throws "Unexpected object in htmljs in toText"

[macrozone]

i am upgrading an ancient app to latest meteor. worked so far, but for autoform-select2 i get:

Unexpected object in htmljs in toText

my template:

<template name="sidebar_products_search_field">
  {{#autoForm id="sidebar_products_search_field_form" schema=schema }}
  {{> afQuickField name="tags" label=false type="select2" multiple=true select2Options=select2Options}}
  {{/autoForm}}
</template>

// helpers:


Template.sidebar_products_search_field.helpers
  select2Options: ->
    tags: true
    placeholder: i18n 'searchPlaceholder'

seems that blaze does not like the select2Options beeing an object. why does this no longer work?