Looks like it has something to do with the shortcode definition being wrapped in <script> tags.
So if the definition is updated to be:
pannellum.viewer('panorama', {
"type": '{{ .Get "type" }}',
"panorama": '{{ .Get "image" }}',
"showControls": {{ .Get "showControls" }},
"autoLoad": {{ .Get "autoload" }},
"author": "{{ .Get "author" }}",
"autoRotate": {{ .Get "autorotate"}}
});
Then it outputs correctly:
pannellum.viewer('panorama', {
"type": 'equirectangular',
"panorama": '31138750083_5e3bfa7df6_o.jpg',
"showControls": true,
"autoLoad": true,
"author": "Benjamim",
"autoRotate": 1
});
So a workaround for now would be to call your shortcode like this:
<script>
{{% panorama type="equirectangular" image="31138750083_5e3bfa7df6_o.jpg" showControls="true" autoload="true" author="Benjamim" autorotate="1" %}}
</script>