Different behavior of context.succeed() vs callback() in AWS Lambda

lambda.js

//
// Lambda's timeout needs to be >5 seconds, 10 should do
//

var startedAt = new Date();

var interval = setInterval(function () {
    console.log(startedAt, new Date());
}, 1000);

exports.handler = function (event, context, callback) {
    setTimeout(function () {
        console.log('returning');
        // v1:
        return callback(null);
        // v2:
        // return context.succeed();
    }, 5000);
};

same as @rodrigomf24, I forgot my db connection open.. after closing it resolved as expected.