Instinct for Cards from Royal Road

[Chaser]

Hey guys,
New to the forum and new to a serious attempt at card sleights. Working through the royal road right now and I can't seem to get "Instinct for Cards" to work correctly. Sometimes it works, but other times cards that shouldn't be out of order are. All the reviews I can find suggest that it should work every time, but I've had it fail three times in a row just now. Anyone else had the same problem with this particular effect?

 

[erdnase97]

read the book over and over, you'll see where you're wrong.

 

[YRAMagicMan]

My issue is that I'd pick cards from the gap i.e if the 7D was selected I'd find the 6D or 8D, not realizing that they were still in sequence. Also, only do 2 riffle shuffles, any more than that kills it. (I hope that wasn't exposure, apologies if it was.)