I dont know if its only happening for Shootmania or Trackmania as well.
Since today if a program is finished you dont switch automatically to next program. Only if the map on previous program ends.
Example:
Battle Program 18:00 - 19:00
Infection Program: 19:00 - 20:00
At 19:00 a battle map wasnt finished, so most of the players stayed on Server until current Battle map was finsiehd (around 19:15). Then they were transfered to Infection Channel.
Please take a look at it

Greetz,
Dmark