Unexpected Minion Instability + warlock Affliction noninteraction

Hey there, I've been using Dark Marionette specters with Coruscating Elixir+Umbilicus Immortalis to hypothetically trigger the death explosion from Minion Instability and warlock Affliction at the same time, but I was finding my damage to be somewhat lacking compared to expected returns.

As a test, while fighting a tanky mob I detonated a few times in the usual way, then unallocated Minion Instability and tried a few more detonations. The damage went up dramatically, which should not be the case (I'm also using Triad Grip to grant phys to fire conversion, so different resists should not be an issue: affliction should be doing fire damage the same as minion instability.) I've since tested in a couple more situations and sure enough my damage seems way higher without minion instability allocated.

It seems that Minion Instability is overriding the Affliction detonation instead of happening at the same time when afflicted minions are reduced to 1hp with Coruscating Elixir, the expected behavior being that they should trigger both at once as they would meet both respective low life and less than 20% life thresholds at the same time.

Now my testing of this has not been totally exhaustive, but the difference seemed pretty dramatic to me. Has anyone else been experiencing this and can they confirm, or am I getting thrown off by some other variable I didn't account for?

https://www.poewiki.net/wiki/Affliction_(skill)

"It is not possible to trigger both the explosion from Affliction and Minion Instability simultaneously through damage over time as Minion Instability will proc first"

So by unspeccing MI forces just the Affliction explosion, which is more damage and lines up with your more DPS.

To clarify, I'm Using Coruscating Elixir on minions with the effect from Umbilicus to set their hp to 1, skipping their hp value past both thresholds at the same time. I'm not waiting on DoT to proc the effects, I'm aware that would only proc MI first.

Update: Tested today on a map with more life and gain life as energy shield mods. I have the necro Unholy Might ascendancy, so Affliction's phys damage explosion deals extra chaos that bypasses ES. With Minion Instability allocated, my minion detonations did nothing to the healthbars if there was still ES, clearly they were dealing no chaos damage, as expected for Minion Instability alone. Affliction was NOT triggering. With Minion Instability unallocated, detonations would pierce some of ES and damage healthbars, as expected, due to Affliction triggering with chaos damage (also as expected, the death explosions dealt significantly more damage.)

Again, I am triggering these effects by setting minion hp to 1 via Coruscating Elixir, not waiting for DoT on my minions. Both effects should be triggering, and they definitely are not. I would really appreciate this interaction being looked at because the current behavior does not make sense.