json_decode() expects parameter 1 to be string, array given

json_decode() is used to decode a json string to an array/data object. json_encode() creates a json string from an array or data. You are using the wrong function my friend, try json_encode();

Set decoding to true

Your decoding is not set to true. If you don't have access to set the source to true. The code below will fix it for you.

$WorkingArray = json_decode(json_encode($data),true);

I think you want json_encode, not json_decode.