APIs are not running in iterations after running a multiple request api

Question

/api/stores triggers an array of different data in postman:

#pre-request script

var managers= pm.globals.get("managers");
var ref= pm.globals.get("ref");
if(!managers && !ref){
     managers=[0,1];
    ref=["QA0","QA1"];

}


var currentmanager=managers.shift();
pm.globals.set("manager",currentmanager);
pm.globals.set("managers",managers) ;

var currentref=ref.shift();
pm.globals.set("refeng",currentref);
pm.globals.set("ref",ref) ;


#Test script

var managers=pm.globals.get("managers");
var ref=pm.globals.get("ref");
if(managers && managers.length>0 && ref && ref.length>0){
    postman.setGlobalVariable("currentmanager",managers.shift());
    postman.setGlobalVariable("currentref",ref.shift());
    postman.setNextRequest("https://staging-api.toters-api.com/api/stores");
}
else{
    postman.clearGlobalVariable("manager");
     postman.clearGlobalVariable("managers");
      postman.clearGlobalVariable("ref");
    postman.clearGlobalVariable("refeng");
}

But when running all APIs in 2 iterations, all APIs that ran under /api/stores didnt run in the 2nd iteration

APIs are not running in 2nd iteration after running a multiple request api