Damage Attenuation Changes:
With our Damage Attenuation changes in The Vallis Undermind, our intention was to normalize the difficulty of boss-type enemies between groups of players. After gauging the community’s response, we recognize that our broad application of that term inadvertently made “objective-type” enemies (ex: Demolishers) harder to kill. We’re redefining our standardization of Damage Attenuation to only apply to True Bosses / HUD Health Bar enemies with our upcoming hotfix, thanks to player feedback.

• Damage Attenuation changes have been removed from regular objective enemies. As a result of this, these regular objective enemies can be one-shotted again.
• Damage Attenuation is now solely reserved for true Bosses and enemies with the HUD health bars.  
• For certain enemies retaining Damage Attenuation, we have adjusted the values to allow for one-shot kills, if a player’s build is powerful enough.

Enemies that no longer have Damage Attenuation:

• Scaldra Dedicants
• Demolishers (including Necramechs)
• Deimos Jugulus
• Deimos Saxum (and Saxum Rex)
• Rogue Necramechs (Voidrig and Bonewidow)
• Amalgams 
• Empyrean Units (Corpus Proxima):
  • Aurax Actinic
  • Aurax Baculus
  • Aurax Vertec
  • Numon (all variants)
  • Vambac (all variants)
  • Zerca (all variants)
• Errant Specters
• Gruzzling
• Necramite
• Sister of Parvos Hounds
• Techrot Babau
• Treasurer 
• Tusk Thumpers (all variants, including Narmer)

Boss Enemies with Damage Attenuation that can be One-Shot:

• Acolytes
• Infested Oni

Our goal was to make powerful builds feel more impactful against Damage Attenuated foes, and with your continued feedback, we can ensure we achieve that together.

The team is continuing to look into other reports of bugs and feedback. Please keep it coming!

Changes:

• The Mote Amp is now automatically equipped once players receive it from Quill Onkko in Cetus.
• Updated the opening animations for the Qorvex Sarcophago Helmet following artist feedback.
  • Also fixed the helmet material being mismatched from Qorvex's body.
  • Also fixed Lubox not being properly credited for this item! Sorry Lubox!
• Increased the brightness of the Fumolo Signa to improve visibility.
• Added some fog to the Grineer Asteroid tileset for lower-spec machines.

Arbucep Gravimag Script:

• With 40.0.1, we fixed Platinum-purchased Arbuceps not coming with a Gravimag installed. As of 5:30pm ET today, a script has been run for those affected.
  • Those who purchased a Gravimag to install have been refunded their Platinum via an inbox message.
  • Purchased Arbuceps without a Gravimag installed now have said item installed, although this was done silently (no inbox message).

Fixes:

Deepmines Changes & Fixes:

• Steel Path Deepmines Bounties now reward 1 Steel Essence upon completion!
• Mushrooms that are ready to be Analyzed are now marked with a “!” in the Field Guide.
• Fixed Archgun Arcane Adapters not being available from Deepmine Bounty drop tables.
  • The original patch notes listed them as Steel Path only, but we've added this item to all Deepmine Bounty drop tables.
• Fixed the Malva node matchmaking into Deepmines Bounties.
• Fixed Acolytes not being able to spawn in certain parts of the Deepmines tileset, resulting in them sometimes spawning very far away from players.
• Fixed Deepmines Bounties being required to deploy Extractors on Venus.
• Fixed missing VFX in certain "visions" from The Prince.
• Fixed a placeholder text string when attempting to Feed the Prince after a new build has been deployed.
• Fixed some minor enemy navigation issues in the Deepmine tileset.

Top Fixes:

• Fixed being unable to start the Chimera Prologue.
• Fixed players being unable to progress in Vor's Prize if they only completed up to unlocking the Mod Segment before The Vallis Undermind was released.
• Fixed Protea's Blaze Artillery receiving unintended stat changes. They have been reverted to pre-The Vallis Undermind values.
• Fixed increasing performance issues caused by Nokko's Sporespring's line of sight checks.
  • This ability now uses a simplified raycast check to find targets.
• Fixed Operators being able to destroy the Rifts created by Xaku's Untime Rift Augment.
• Fixed Helios' Investigator Precept not working for Clients in missions started via a Streaming Tunnel (i.e. Fortuna Elevator, etc.).
• Fixed Lavos' Transmutation Probe auto-casting when combining an element involving Electricity.
• Fixed cases of being unable to progress in the Angels of the Zariman quest.
• Fixed ragdolled enemies sometimes instantly dying on uneven terrain.

Performance Issues & Crashes:

• Fixed significant performance issues caused by the Tenet Arca Plasmor's VFX.
• Fixed performance issues caused by Slam VFX.
• Fixed Ivara's Concentrated Arrow crashing the game if shot at a Nullifier Bubble.
• Fixed a crash caused by Redeemer Prime.
• Fixed a crash when returning to Fortuna from a Deepmines Bounty.
• Fixed a rare crash on mission end.

General Fixes:

• Fixed Helminth subsumed Smite having an incorrect Radial Damage value. 
  • It now matches Oberon's Smite!
• Fixed the Altra Sentinel Wings having collision.
• Fixed an unintended context action appearing on the Navigation Console after generating a Technocyte Coda.
• Fixed background gameplay elements clipping into the Mod Menu.
• Fixed the Mod Menu's background disappearing after entering and leaving the Ayatan Treasures screen.
• Fixed Valkyr's Ripline SFX being a full volume for squadmates, regardless of their distance from the casting Valkyr.
• Fixed being able to trade the Yareli and Merulina Prime Scene.
  • If you traded away your Scene, please contact our support team for assistance. 
• Fixed missing texture on Natah's transmissions.
• Fixed the Companion Riven Mod displaying a droptable instead of item description in Cephalon Simaris' Offerings.
• Fixed broken animations when previewing Warframes in the Conclave Arsenal with Melee Doughty equipped.
• Fixed Sprodlings from the Sprodling Ephemera disappearing while in the Orbiter.
• Fixed a map hole in the Grineer Sealabs tileset.
• Fixed a spot where Otak can get stuck in Isolation Vaults.
• Fixed a script error after completing a Bounty Stage taken from a Radio Console in the Plains of Eidolon after a host migration.
• Fixed a script error caused by Styanax's Tharros Lethality Augment.
• Fixed a script error caused by Nokko's Reroot.
• Fixed a script error in endless Void Fissure missions, resulting in enemy levels sometimes randomizing to a negative value after a Host Migration.
• Fixed graphical errors that would occur if DLSS and SSGI were enabled at the same time.

For list of known issues that are on our radar, visit our dedicated thread: https://forums.warframe.com/topic/1470876-known-issues-the-vallis-undermind/