I just got a Vault Card reward (Mercedi) to drop as a Phosphene. Was this always possible?

https://preview.redd.it/wfi6d3ssus9h1.jpg?width=1920&format=pjpg&auto=webp&s=ae8f6e4bd8fdafbf0c5d17ec079a7e6a1d95d636

https://preview.redd.it/hifyl4qtus9h1.jpg?width=1920&format=pjpg&auto=webp&s=3a00a49e5bd3fff42b50b76d8372a1326da0e2c5

During my first playthrough of the new bounty pack, my story kill on CL34.n.R actually dropped this gun as a phosphene.

First of all I didn't know these could world drop, and more bafflingly as phosphenes?? Lootlemon does not list this weapon as being able to drop besides claiming from the vault card, nor the possibilty of a phosphene.

2nd pic is showing that I don't have the phosphene 100% challenge and that the Mercedi does not show up on the list. Could this be a one of a kind drop, or caused by some undisclosed changes in the new patch?