I read your comment regarding why the tannins increased in the glass after 10 minutes. I have to say that although I can’t answer that question specifically, I can say that almost all wine will change once the cork is removed and poured into a glass. Wine is a living thing and once the cork is removed and the wine poured in the glass, it will begin to either evolve or die.
A young wine will evolve and change and in some cases, like this one, they can become out of balance. Due the fact that the wine had such tremendous concentration and the fact that after a few days opened had improved, indicated to me that this had some storage potential. This is not an exact science by the way, more my opinion based on my experience and what the wine was “saying to me”.
Once the cork is removed from an older bottle of wine and poured into a glass, it can do the opposite. It can be fine for 10 or 15 minutes, perhaps more, then can be completely dead.
Oxygen can bring life to a young wine but can be the enemy of old.