Gokstad Officers are immune to any form of Armor Reduction

[Duality52]

For reference, Gokstad Officers are Grineer identical to Heavy Gunners that command a Crewship, wielding a Karak Wraith (one of the few enemies using a weapon variant such as the Sentient Research Director using a Supra Vandal) and summoning Kosma Roller Sentries.

Below are images of me shooting my Vectis Prime of the same build against the Officers with and without a Corrosive proc, followed by Corrosive Projection and no Corrosive Projection.

Without Corrosive Projection:

• No Corrosive Proc: https://steamuserimages-a.akamaihd.net/ugc/770611292004866763/B67CE17CF2874634275010A6F90A638157731F9C/
• Corrosive Proc: https://steamuserimages-a.akamaihd.net/ugc/770611292004867238/BDAFA40E079AA64C1AB96370338ADE297F2688E4/

With Corrosive Projection:

• No Corrosive Proc: https://steamuserimages-a.akamaihd.net/ugc/770611292004867588/692F2747A0BAC93D5C00F434664D53203F6F7C81/
• Corrosive Proc: https://steamuserimages-a.akamaihd.net/ugc/770611292004867880/472AA94F8B5441B363D0ECD405D2154A7F53D710/

Additional testing showed that even Shattering Impact and even the new Heat procs do not reduce their Armor at all. I did not test Kavat's Sharpened Claws or any other Augments that reduce Armor.

While you can just go for a Viral/Hunters Munition build, that still does not excuse how overtuned these Grineer are, with health and armor values surpassing Napalms with damage higher than even the Elite Terra Corpus.

[ComediNyan]

Stumbled on this myself, and I was confused if this is a simulacrum bug. Shame this is this way- they would be a great way to test dps otherwise.
At least viral procs work on them.