EDIT: Fixed as of 0.2.0!
Original post:
Pretty sure when you originally added _update60(), you compensated for the doubled frame rate when returning time() values, but these days time() is running at double speed when you have _update60() instead of _update().
I noticed this when playing with a simple seven-segment-display demo. Here's one that uses update() and updates once per second as expected:
And this is the same cart, but switched to _update60() and runs twice as fast: