When this augment was first introduced, additional loot would only be generated if the enemies were killed by Tentacle Swarm, making this augment less effective at higher levels due to enemy health and armor scaling. Hotfix 17.0.4 changed this to its current effect, in exchange for the additional loot chance no longer being affected by Ability Strength.
Warframe Loot Abilities will again be able to yield multiple-drops from already looted corpses. A single enemy can be looted by at most one Ability from each group - which is how it worked before, this just clarifies it. Warframe Looting Abilities have been split into separate functionality groups for clarity:
Loot while alive: Ivara
Loot petrified: Atlas
Loot on death: Wukong, Khora, Hydroid. An enemy can only be killed once, they can’t ‘die’ multiple times.
Fixed Chesa/Desecrate double dipping with Hydroid/Khora.
Added info: When we added the Nightwave challenge for the Silver Grove, we encouraged a return to content that normally would have been fine. A small handful of players found an exploit and as we looked into things, we thought we fixed the issue with the new Chesa behavior that could lead to problems. We didn't. We decided to cut a bit deeper. Ivara's looting ability is now the only one that stacks with other looting because it works while alive. If a target is dead, a successful loot now happens once, no matter the source. However, multiple can attempt to loot the same body. Yes... this is different from how it previously behaved, but this is the new intended behavior.
The drop rates from the Pilfering Swarm Augment Mod will no longer be affected by Power Strength.
The Pilfering Swarm Augment Mod will now generate drops for enemies that are slain being held by tentacles, not just dying from the tentacle’s appearing. In short, enemies don't need to be killed by the tentacles to have an added drop chance.