Spell jumping up the stack?

~~I just had the weirdest thing happen in a game. I was playing against mono blue and cast Mortify on their creature. I had 2 Dovin's Acuity on the board and they triggered. Before any of this resolves my opponent casts Dive Down to save his creature. I respond with Vraska's Contempt (trigger, trigger again) and he Spell Pierces it.

I only have 1 untapped land here, so I can't pay the pierce, Contempt is countered. I then accept the two Dovin's Acuity triggers to get them into hand and after they are returned to hand Mortify is suddenly resolved ahead of the Dive Down and the inital two triggers (which are still below the Dive Down in the stack)~~

Edit: False alarm. Digging through the history of the game has showed me that I am wrong and confused things. It appear I cast Vraska's Contempt first, he Dive Down'ed, I responded with Mortify, and the he accidentally Spell Pierced the Contempt. So no bug at all, just a really cluttered stack and me failing to remember my sequencing properly.