EspruinoWifi - Ping function / Default gateway

Dear Grodon, I use wifi.ping with setInterval under v1.96 and NodeMCU, it have memory leak in case if I use callback function and function wifi.ping always return undefined. It's NodeMCU issues?

setInterval(function(){
    console.log(wifi.ping("192.168.2.1", function(b){
      //console.log(b);
    }));
    console.log(process.memory().free);
  }, 5000);

result:

undefined
1371
undefined
1303
undefined
1218
undefined
1134
undefined
1061
undefined
976
undefined
891
undefined
806
undefined
721
undefined
636
undefined
551
undefined
466
undefined
381
undefined
296
undefined
211
undefined
126
undefined
41
Execution Interrupted
New interpreter error:
Execution Interrupted