Here is an excerpt from
the patch notes from Orsinium's launch:
Clarified the tooltip for the Impenetrable Trait on armor to clearly state that it reduces crit damage from other player characters.
Despite being in the patch notes,
this tooltip clarification never actually appeared in Orsinium. It is still missing in Thieves Guild, and it is still missing in Dark Brotherhood on the PTS. It simply got lost somehow.
This is what the tooltip looks like on Live and on the DB PTS:


Yes, this is an old bug. And a very minor one. So why am I bringing this up now? It's because during the recent ESO Live episode, when asked about Impenetrable not dropping in PvE, Wrobel said something along the lines of PvE players not really knowing what this trait is for. And this is true--many players don't know that PvE enemies can't crit and thus Impenetrable is a PvP-only trait.
If the reason (or part of the reason) for omitting Impenetrable from PvE loot tables (Undaunted chests, vWGT, vICP, etc.) is because people might be confused by the trait, then the solution isn't to omit the trait from the loot table: the solution is to clarify the tooltip as originally intended.
Whatever the case, it would be nice if it this intended fix was actually implemented.
@ZOS_JessicaFolsom
Nightfighters ― PC/NA and PC/EU
Dungeons and Trials:
Personal best scores:
- Dragonstar Arena: 46817 (NA)
- Maelstrom Arena: 600526 (NA)
- Blackrose Prison: 99274 (EU) (Unchained)
- Maw of Lorkhaj: 165227 (EU)
- Halls of Fabrication: 220708 (NA) (Tick-Tock Tormentor #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12)
- Asylum Sanctorium: 114957 (NA) (Immortal Redeemer #1, #2, #3, #4, #5, #6, #7, #8, #9, #10)
- Cloudrest: 131256 (NA) (Gryphon Heart #1, #2, #3, #4, #5, #6, #7)
- Sunspire: 250866 (EU) (Godslayer #1, #2, #3, #4, #5, #6, #7)
- Kyne's Aegis: 235841 (EU) (Dawnbringer #1, #2, #3, #4, #5, #6, #7, #8)
Dungeon trifectas: