I am a little bit unsure about just what the first stage and second stage are on the Soyuz. The basic design goes all the way back to the first Sputnik launch, which five units all firing together at launch: the four boosters and the core. When the boosters have burnt all their fuel they detach, leaving the core still burning.
The pictures show one of the four boosters having a bad separation.
If one control module failed, out of four, it all makes a lot on sense, if what I am thinking of as booster separation is what is been called first stage to second stage.
