Before anyone asks, no this
does not deal with the penetration gems.
Normally, when you vendor Bitterdream/Replica bitterdream, you gain skill gems that correspond to what sort of supports the unique item gives.
Normally, Replica bitterdream supports gems with 3 level 10 supports (Ice Bite, Immolate & Innervate) and 3 level 1 supports. (Elemental Penetration, Unbound Ailments, Inspiration)
Vendoring this gives you 5 gems you'd expect: all 3 level 10 supports, the level 1 unbound ailments, and a level 1 Fire/Cold/Lightning gem. (at random, with a recipe to receive a level 1 Elemental Penetration instead)
However, instead of receiving a level 1 Inspiration Support Gem in the mix, you receive... A level 1 Unleash Support gem, which isn't even part of the item. This behavior remains whether you are vendoring Replica Bitterdream on its own, or including the trio of level 20 Fire+Cold+Lightning Penetration gems so your result includes an Elemental Penetration gem.
tl;dr:
vendoring Replica Bitterdream gives you a level 1 Unleash instead of a level 1 Inspiration.
Bug Report #: Irrelevant, as this bug is trivially reproducible.
Reproduction: Get a Replica Bitterdream by any means. Talk to an NPC vendor and go to the sell screen, and place it in your offer.
Screenshot: Attached is a screenshot showing both the properties of Replica Bitterdream (including the level 1 Inspiration and no form of Unleash) while
also showing the vendor recipe result from it, with no Inspiration, and what is clearly an Unleash Support gem.