Act 3 - Zicoatl, Warden of the Core not dropping Large Soul Core.

I am having an issue on my account associated to the same bug reported back in DEC/JAN Bug report #3103875416.

Basically I am stuck in campaign 3rd act and cannot proceed since the quest Legacy of the Vaal is bugged. After killing Zicoatl I do not receive the large core to progress.

Please let me know if this can be fixed as I spent a lot of time to get my character to lvl 46.

Ver: (Standard League), Geo: Japan Realm , Character name: ZUTTOME

I think you are looking for the PoE2 early access bug report forum
https://www.pathofexile.com/forum/view-forum/2214

Have you attempted to move out of the zone then creating a new instance of the are to ggo in and kill Zicoatl again?