Perhaps I've misunderstood the requirement but that output looks as I would have expected.

• Two events at time 07:03:08, event with amplitude 2 chosen.

• Two events at time 07:03:09, event with amplitude 2 chosen.

• A single event at time 07:03:10, the only event (with amplitude 6) chosen.

• A single event at time 07:03:11, the only event (with amplitude 7) chosen.

So far as I can tell, that satisfies the requirement "I'd like to keep only the largest magnitude within each second" to the letter.

Perhaps you could explain further in which way it is "broken."

Cheers,

JohnGG