Engagement Engine and Custom Fields

Content

We are having issues getting the value of a custom field to pass to the chat launch page from an SPAC offer in Engagement Engine.  

We manually placed the SPAC widget on our pages using the script below.  When using this script, the value of cart is passed into the page in the URL (_icf_3/Cart/incidents.c$proactive_chat_source/Cart).

However, when we remove the script below and add our engagement engine tags back, then add the string "{\"3\":\"Cart\"}" to the custom fields parameter in engagement engine, this is what we see in the URL when we accept the offer: _icf_3/%22/incidents.c$proactive_chat_source/%22