Giveaways not increasing Contributor Level(although adds to my gifts given)

Perhaps you I'd like to read FAQ about Contributor Value and Levels. The game was probably given away for free.

Tumblestone is given free many times its considered as NO VALUE. You should check FAQ.

Games that were previously given for free (for example, Tumblestone) do not increase the level of the contributor

From above mentioned FAQ:

What are "No Value", "Reduced Value", and "Full Value" giveaways? How do they affect my overall contributor value?
When creating a giveaway and selecting a game, you'll notice "No Value" games are marked with a double asterisk (**), and "Reduced Value" games with a single asterisk (*). If you hover over those icons, you'll see the effective date for the value adjustments. For example, if a game is marked with a single asterisk (*), and hovering the icon shows "Reduced value since January 4, 2018", this would mean giveaways created for that game on January 4, 2018 or later will receive reduced contributor value. Games typically receive no value or reduced value when they're featured in bundles, heavily discounted, or available for free in online promotions. Their values are adjusted this way to better represent their true value. Keep in mind, the asterisk icons are just for reference, and the value of a game can be backdated if we need to make retroactive changes.
Games fall into one of the below three categories.
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No Value
No contributor value when given away after the effective date.
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Reduced Value
15% contributor value when given away after the effective date.
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Full Value
100% contributor value when given away.
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If you visit your profile, you can see a breakdown of your previous giveaways. If you hover over the "Gifts Sent" number on your profile, you'll see the number of gifts you have given away in each category.
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For example, you give away three games. Game A is $10.00 and it has no value. Game B is $20.00, and it has reduced value. Game C is $50.00 on Steam, and it has full value. Once your giveaways have ended and the gifts have been received by their winners, you will see the updated values on your profile. In this case, you would see "Gifts Sent: 3 ($80.00)". This would show that you have successfully given away 3 gifts, and their current list price on Steam is $80.00 in total. If you hover over the number of gifts, you would see you have one "No Value" gift, one "Reduced Value", and one "Full Value". If you hover over the dollar value, you would see you have a contributor value of $53. It would be calculated as 0% of the gift with no value (0 x $10.00 = $0.00) + 15% of the gift with reduced value (0.15 x $20.00 = $3.00) + 100% of the gift with full value ($50.00).

You're sacrifice did not please the CV gods

Well....Atleast it made someone happy

Tumblestone is especially problematic... I'm not sure that the full game has actually been given away for free (it may have), but there's a free trial key that has inundated SteamGifts. Lots of scammers have given it away, and a lot of well-meaning people who thought they were giving away full versions have given it away (I got one from the latter type of user).

Once you get the free trial key, Steam thinks you own the game (i.e. Steam apparently gives the same app ID to both the free trial and the full version), and the only way to actually get the full game them is to upgrade in-game. Whether or not the full game has been given away for free, that's a pretty good reason for the game to have no CV.