Honestly, that's probably the case, at least partially.
Personally, I can't stand 2,4-dithiapentane - even the smell of it bothers me to the point where I find it difficult to eat my own meal if the table next to mine orders "truffle fries" or whatever. I haven't intentionally touched the stuff to my tongue in well over a decade. But if someone likes it, to each their own.
The other problems, aside from palate acclimation, are two: First, heating it up doesn't concentrate the flavor/aroma, it dissipates it faster. In the moment it's warmed, and for a few minutes, it's much more intense because you're activating all those volatiles, but that moment is fleeting. Shave some fresh truffles on still-warm buttered pasta. Take a big whiff and a bite for reference. Then let it sit there and come back in an hour. Not gonna be so impressive.
Second, most of the aromatic volatiles just aren't soluble in fat. You can't actually "infuse" those molecules into oil, butter, etc - they're not going to bond with the fats, though some will get "trapped" between them.
The combination of the two factors - the heating and the insolubility - is working against your hoped-for result. And more than you'd realize is probably escaping right through the plastic. Those molecules are small, some will permeate water-tight materials. Depending what mil bags you're using (Foodsaver-style or chamber vacuum? Just curious) I would wager you had some at least mildly truffley water in the bath for a bit.
If determined to make a butter for long-term storage, though, I'd say just shave it into room temp butter like you would any compound butter, and seal it in the thickest bags you can get. Then check it in a month - slice it onto a steak, mount a sauce with it a la minute, whatever - let the heat in the moment do its thing.
There have been some inroads made to preserving the aroma & taste, but nothing perfect. Alcohol appears to be the best method - any neutral spirit, the higher the proof the better, but you want at least 100+ proof. Then you can add a splash to sauces later (or better, just put it in cocktails...) - I did a bottle a couple years ago of Perigords in an unaged Armagnac (so... not neutral, I just thought they'd go well together) which was very nice, but in the end better for straight sippin' than cooking with. The moment you cook with it, a lot of it evaporates along with the booze. (That said, all the supposed "truffle vodkas" on the market contain dithiapentane, so hard pass on those...)