Hello,
I've seen when ADV interval is near than 1 second, the sniffer cacth the same adv twice in diferent channels, but if the adv interval is near to 50 ms the sniffer only cacht 1 per ADV, and athother question, if adv is send every 800ms I capture the adv every 800ms and the same adv 400ms after. I using the same code example for long range blog.nordicsemi.com/.../tested-by-nordic-bluetooth-long-range