I let my previous post vanish for the collection changed recently when it comes to emblems (making the thought I had obsolete). Back to your problem: It seems, your memory played a trick on you, look at this: https://www.d2checklist.com/2/4611686018464254625/triumphs/tree/1186584469 the Now You're Just Showing Off triumph shows 503/2500 meaning you did not earn this emblem. You got the first one for the 500 kills though (i think it is called "the weight of guilt")