Hello, how u doing?

I just arrived home from school and I saw something interesting on a plane. I live near MMMX and I get to look at aiplanes no matter how high they go  ;)  So I believe I saw a Boeing 737-700 from Aeromexico turning for final approach for 05L or R runways for at least 20 seconds and I'm pretty sure their stobe lights were off. It was already late dusk and I was very surprised only beacon, navigation and wing lights were on.

I thought they were a MUST lights for traffic caution or/and a FAA rule.
Maybe pilots missed to turned them on, I don't believe people at AM would let it fly if it had a light problem.

Rigo