How much time BEFORE a game entered a bundle would be traced back the contribution value?

EVERYTHING will be bundled in time, so it doesent matter :D

All game will be bundled, all game will decrease in value.
Don't buy copies of the same game. I'm not sure but I don't think SG wants people buying games just to increase CV fast anyway.

bundled items are bundled retroactively to the time it was bundled/extremely discounted. If you create the giveaway before that date you will get full CV

It would probably be good to know the game it concerns, since one could look into if it was bundled before.

Very-very likely the same discount made you think it's a good purchase pushed it into the bundle list. :\

Yeah, it seems a bunch of things were added to the list recently. The adding to the list usually doesn't happen as soon as the bundle is there, but as soon as the person who adds the stuff notices and has the time. "Bundled" reasons could also be stuff you can't really notice, like the game becoming 90% off when the Russian prizes are compared to North-American.

I lost a bunch on Age of Empires III only yesterday :(

As others have said, if a game has ever been below approximately 95% of the base price, including when converting from other countries/currencies, it will eventually be marked as bundled. If you give that game away after it was 95% off or more, even if it's not on the bundle list already when you give it away, it's extremely likely that it will eventually be added retroactively, and your CV for it will decrease.

In this case, I'm assuming from your gifting history you're talking about Deep Black Reloaded. It was added to the bundle list on February 3rd of this year, retroactive to November 16, 2014, meaning if you gave it away any time after that 2014 date, your CV now went down. It looks like this is probably because of the Steam price in Russia at the time in this case. On November 27, 2014, which is as far back as this listing goes - https://steamdb.info/app/204760/ , the price of the game on Steam in Russian rubles was 74p, which it looks like was approximately $1.50 U.S. at the time, 95% of the retail price of $29.99. It's also been that low, and even lower, in subsequent sales, including this winter's steam sale.