Check whether the object is already in JSON format to avoid double serialization.

[mmishyn]

Colbox \ System \ Core \ util \ Util.cfc

string function toJson( required any obj ){
// https://cfdocs.org/serializejson
// We default to "struct" serialization for queries. The CFML defaults are dumb and just nasty!

	if ( isJSON(arguments.obj) ){
		return arguments.obj;
	}
	
	return serializeJSON(
		arguments.obj,
		"struct",
		!server.keyExists( "boxlang" ) && listFindNoCase( "Lucee", server.coldfusion.productname ) ? "utf-8" : false
	);
}