There is a good chance you'll find a bug in Syberia 2 that takes place in the second location of the game, half-way through the adventure.
It is game-wrecking, and it could be triggered easily.
I don't think it is OS dependent, so it could be present regardless of the platform you play it on.
Worse still, so far there seems to be no troubleshooting for this problem.

Here's my warning about it.

If the spoilage of one puzzle in the whole game is enough to ruin your playthrough, then just read the first section: TS;DR (too spoilery didn't read).

TS;DR (TOO SPOILERY; DIDN'T READ)
Be VERY careful when you create candles. Making pairs will put an end to your game.
So better don't make any until you need one.

If you don't mind a bit of spoilers, carry on.

<CONTAINS SPOILERS FOR ONE PUZZLE>
DETAILED AND SPOILERY EXPLANATION:
Creating more than one normal candle at the Monastery will end your playthrough.
In the second location of Syberia 2 you climb to a monastery. Therein you will need create a healing candle.
As soon as you enter the cloister, there is a machine to create candles that is very easy to use and can be operated as soon as you find some matches. That machine will eventually create the healing candle you'll need (called in-game "Herb Candle").
If you, by mistake or by testing your environment as a curious gamer is wont to do, happen to create more than one normal candle before creating the Herb Candle, then you will never be able to progress further.
The reason being this: When Kate makes one candle she can take it from the mold and place it in her inventory. If she creates a second one, she will say that she already has one and won't take more. But the new candle will remain in the mold area of the candle-making machine.
When you eventually return to create the healing candle, the second normal candle will still be in the machine, Kate won't be able to take it out because she already has a normal candle, and since there is no free space on the mold to fit the healing candle you'll start a catch-22 loop that will never be broken. The Herb Candle will never be made.
I never found a place where Kate could use the normal candle, so I could never get rid of it.

The problem takes place almost mid-way through Syberia 2 and the game has only one save. So by the time you notice the mistake it will be too late to avoid the autosave, and, as was in my case, too far into the game to want to restart the whole thing.

FINAL NOTE: There's a report of this exact same problem at Microids' official website, and it has been sitting there, unanswered, since 2017. This is the link to that post.

This would be fantastic news if it helps me. I'll re-install the game ( as soon as I finish the 4 or 5 I have mid-way... yes, I juggle games quite often :D ) and try that out. And this answer came almost the day of my birthday, so that is an extra point of greatness.

If all works well when I play it and can get rid of the regular extra candle, I will tag your post as the SOLUTION.

In any case, thanks a lot for coming here to tell me and any other unfortunate that arrives here afterwards.
:)

DONE !
It was not a bug after all, but an astonishingly obtuse game desing decision, so ridiculous that it looked like a bug.

The non-spoilery version of the solution is above, in the post by Jordboy1, who found the solution to the problem and saved me from hours of repeating my steps.

Below is the unashamedly spoilery one, so beware !

YONDER THIS POINT THERE BE MUCH SPOILAGE

1. After solving the riddles of the Library you will have in your possession a candle-holder.
2. After talking with bedridden Hans you will have the mission to make the Herb Candle of the problem.
3. Now that you are in Hans' room with your useless extra candle, go to the table, select your candle-holder (which I believe is called a relic in-game), and place it there.
4. Now select the useless candle, put it in the candle-holder, light it with the matches and FAIL the attempt to cure Hans on purpose (since you still don't have the Herb Candle you have been wanting to craft ages ago).
5. Only then, when you (the character) outloud realizes what you (the player) have already known since hours ago is when you can get rid of that wax ballast.

You can now finally proceed to the candle-making machine and produce the one that will heal Hans.

And that is that, ridiculous problem solved.
All of which could've been remedied with a button in your inventory that said DROP ITEM.
But as Jordboy1 said, that's old time point-and-clicks for you.