According to Jim Oberg, the next Soyuz flight might be delayed because of an explosive bolt.
It might force the current crew to land in the dark.

It reminds me of Dewinne's flight, which took place 2 days after the sheduled time, after a Soyuz rocket exploded earlier (at Plesetsk). And they also landed in the dark (no pictures exist of the landing under parachute also because the Soyuz has no light, I believe).

Jean-Pierre Haignere's father told me, at Le Bourget, that his son's first flight had known an electrical shutdown at the launch base, just before liftoff. The electricity came back right before launch and they left the ground one second late.
This is to show how resilient the Russians are. And they haven't had casualties during spaceflights since 1971.

Raoul