RAW, Sneak Attack can only be allied ONCE per turn. That means you can only apply it once during your turn, regardless of be number of attacks you have, and on any of those attacks. Opportunity or Out-of-Turn attacks, however, can apply it again.
— Matthew Mercer (@matthewmercer) 20 aprile 2018
I was curious about your House Rules, not trying to critique. Much love 🙁 It’s all good! No house rule, Nott should have been applying it to either attack. If it was missed, it was a mild oversight. 🙂
— Matthew Mercer (@matthewmercer) 21 aprile 2018