Does the Battle Pass Prismana egg hatch Perfect?

The guarantee is in the egg's item description, and the hatching screen never repeats it. So if you hatch it and nothing on screen says Perfect, nothing has gone wrong. Read the description while the egg is still in your bag, and check the potential on the Aniimo itself once it hatches.

The Aniimo you get is a Prismana form, Formentus in this case, so the egg gives you a rare form and top potential together. That makes it one of the safest Perfect sources in the game, because other routes are less reliable. Perfect-quality Aniimo can come from other eggs, Prismana eggs from Operation Egg Heist and the Homeland level 15 reward included, but only sometimes.

Using a Sparkling Cube on the egg

Prismana and sparkling can stack on one Aniimo. A Prismana egg can hatch sparkling if you use a Sparkling Cube on it, so the Battle Pass egg is the obvious place to spend one. You keep the Perfect guarantee and add the sparkling on top.

What this egg will not give you

It hatches a regular Prismana form, not a dark one. Dark (Umbra) Prismana forms come only from Prismana eggs taken in Egg Heist, and those are guaranteed to hatch an Umbra Aniimo. If you want an Umbra Prismana, you have to farm Egg Heist. The Battle Pass egg won't get you one.

Not settled: Which species the Battle Pass Prismana egg holds is not settled across editions. This egg hatches Prismana Formentus, but the advanced edition of the Companion Manual pass is also listed as awarding a Prismana Flamentus egg. The Perfect guarantee is confirmed only for the Formentus egg, so read the description on whichever egg you actually receive.