Comment by jchavannes

Yep. This is the code that's causing it[1]:

  var now = Date.now()/1000;
  var dt = now - then;

Adding this line fixes it:

  dt = dt > 1 ? 1 : dt;

[1] https://github.com/grondilu/grondilu.github.io/blob/47d41d/p...