Is there a [t͡s] in "с юга"?

Question

In this rendition of the Весеннее танго, I hear "с юга" (for example at 1:04) pronounced as ['st͡sjʉgə]. Am I hearing it right, and, if so, what's the [t͡s] doing there? Is it part of some more general thing? I hear it every time German sings the words so it doesn't seem to be accidental, and, as far as I know, she was a native Russian speaker.

I'm asking this because, if it's a real thing, it's very strange to me as a Polish speaker. What we'd do with the onset of the first syllable is voice the /s/, but then the Polish version of "c" is "z", and it's voiced by default. I don't think Polish speakers insert extra affricates anywhere. (I could be wrong of course, but I'm sure enough to be almost shocked by the Russian thing --- again, if it's real.)

Answer 1

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I listened to a few times a phrase "с юга" (0:20, 1:04, 1:45), but "с тьюга" I heard only in the second chorus (1:04).
May be it is a defect of record or slip of the tongue?

Answer 2

s is alveolar (and voiceless) while j (in ю = йу) is palatal (and voiced).

In normal speech one first releases the tip of the tongue from the alveolar ridge then moves its back to the hard palate while adding voice. This makes two distinct sounds, [s] and [j].

However, while singing it's somewhat hard to move the tongue this way. It's easier to "roll" the tongue over the palate. During the roll the middle of the tongue touches the place between the alveolar ridge and the hard palate and is instantly released (as j is an approximant). This results in a palatalized alveolar plosive, i. e. Russian ть ([tʲ]).

You may easily reproduce this if you roll the tongue over the palate while articulating the phrase, as if you were trying to use the tongue to help blocking the air between the two sounds.