H1B stamping just before petition is about to expire


My petition will expire on 31 August 2018 ( 01 sept 2017 to 31 aug 2018). My stamping is on 9 the August 2018. Which is just 20 days before the petition gets expired. I have few questions like

  1. what kind of questions VO may ask ?

  2. are there any chances of rejection as my petition is about to expire ?

  3. should I be cautious any ways ?