Hunter - Alien Encounters // Not Properly Discounting

While playing as a hunter, I received 2 copies of “Alien Encounters” in hand that is supposed to be discounted per each discover; one was discounted properly, and the other had no discount. I had played “Rangari Scout” previously, and received the copy by using “Tracking” to discover “Alien Encounters.”

https://www.reddit.com/r/hearthstone/comments/1h21e4o/ummm_i_dont_think_this_discounted_right/#lightbox

It’s odd that one copy would be discounted, but not the other.

Was there some effect that increased the cost for one of them, like did you play it while your opponent had an Ice Trap secret?

Also, that Reddit link goes to a completely empty thread. No post body, no comments, no screenshots, just a title and nothing else.