I attempted to solve this through tech support but failed.

Lines 4 and 5 reassign the variable "mymap_pair2". Why does this fail?
Lines 11 and 12 attempt to add a Map_Pair object to a Map. According to the documentation this should be a valid operation. Lines 8 and 9 do this and don't fail. Why do lines 11 and 12 fail?

// this is line 0
var my_map = Map();                                         // works. -- my_map is a : chai:Map :: .size = '0' :: to_json = '{}'

var mymap_pair2 = Map_Pair();                               // works. -- mymap_pair2 is a : chai:Map_Pair :: .first() is a chai:string ; .second() is a chai:UNDEFINED
mymap_pair2 = Map_Pair();                                   // DOES NOT WORK --- WHY???
mymap_pair2 = Map_Pair("key string 3","value string 3");    // DOES NOT WORK --- WHY???

my_map["key string 1"] = "value string 1" ;                 // works. -- my_map is a : chai:Map :: .size = '1' :: to_json = '{"key string 1" : "value string 1"}'
my_map.insert(["key string 2":"value string 2"]);           // works. -- my_map is a : chai:Map :: .size = '2' :: to_json = '{"key string 1" : "value string 1","key string 2" : "value string 2"}'
var mymap_pair = Map_Pair("key string 3","value string 3"); // works. --mymap_pair is a : chai:Map_Pair :: .first() is a : chai:string ='key string 3' ; .second() is a : chai:string ='value string 3'

my_map.insert(mymap_pair);                                  // DOES NOT WORK --- I THINK THIS SHOULD WORK ACCORDING TO DOCUMENTATION
my_map.insert(Map_Pair("key string 4","value string 4"));   // DOES NOT WORK --- I THINK THIS SHOULD WORK ACCORDING TO DOCUMENTATION
// this is line 13