Background tasks in deepSleep() ?

Hello!

I have an espruino original v1.3b with the latest 1.99 firmware, when I run this:

reset()

setDeepSleep(1);
setBusyIndicator(LED1);
setSleepIndicator(LED3);

var t;

setInterval(function () {
  t= E.getTemperature();
}, 2222);

save()

and plug it into a wall charger, the blue light blips sometimes out of sync with the 2.2 seconds red light. Does it mean it's briefly coming out of deep sleep every now and then for some reason?

https://youtu.be/4OzA4lZ5eC4