Free minutes - Why is SIM1 still connected to the network after all free minutes have been used?

Yes, it is correct, however it also depends on the Mode of switching SIM card settings (Gateway configuration > GSM outgoing groups > Mode of switching SIM card).

Please see the complete description of modes below.

Mode of switching SIM card defines how the SIM cards will be used in the selected GSM group

• SIM # - the SIM cards in the position # will be used only, no limitations will be applied.
  
  
• By time - the SIM card will be switched according to the Time of use parameter and call timer limitations.
  After exceeding limits on all SIMs, SIM1 will be used for incoming calls only.
  
  
• Random - the SIM card will be switched randomly at defined time intervals and according to call timer limitations.
  After exceeding limits on all SIMs, SIM1 will be used for incoming calls only.
  
  
• By time and limit; then SIM card 1 - the SIM card will be switched according to the Time of use parameter and call timer limitations.
  After exceeding limits on all SIMs, SIM1 will be used without any limitations.
  
  
• Random and by limit; then SIM1 - the SIM card will be switched randomly at defined time intervals and according to call timer limitations.
  After exceeding limits on all SIMs, SIM1 will be used without any limitations.