Did the Amanamu's Void thing ever get credibly confirmed?

I never get an omen of liege when he dies outside the cloud. I don't always get an omen of light or echoes, but when he dies inside the cloud 99% of the time it's a liege.

It does work like this but it is kinda janky. Normally, you shouldn't be able to kill the monster if you're outside the cloud anyway, but it still happens a lot that you kill it while being outside but it still drops the liege omen.

It's pretty real. You will only get oven of the liege if it dies in the cloud. I have done this personally, but i didn't farm it much. Imo it's really awkward and i just don't find it very fun.

I don't recall official confirmation. We have, however, seen more than sufficient amount of results comparing within the cloud vs outside the cloud to believe it is very much indeed the case.

It's very reliable.

Considering they nerfed the effect yes it was working

https://www.pathofexile.com/forum/view-thread/3912620

3 patches ago: https://www.pathofexile.com/forum/view-thread/3912620

The bug fix confirms that the void causes an additional omen drop,  at least. 

Check this out, explains and proves it. Although it has been nerfed now https://youtu.be/sNww3Gh0sLA?si=hLFoSI-fTlbNBqe5

It definitely works like this, when my damage was not that high, I had time to lure them out and kill them and get Omen of light or something.
When I switched to Doedre's Undoing / CoC Comet I was not able to coordinate anything with Abyss any more, anything just got blasted away as soon as I came near and never got a single decent drop of it again, so basically gave up farming on them.

They must have nerfed it, I got a light yesterday, for the first time in a week, and 7 always use 1 abyss precursor in maps. Got a ton of abyssal echos