When I arm the SAI from the activation point I notice that the partitions associated with it are switched off and I have to pass the key again to activate it.

It is a normal situation which depends on the message handling of arming/disarming inherent in the control unit: it is therefore important to include the SAI zones of the activators in the relative partition carefully, especially when such a partition is associated with multiple devices, activators or control unit/keypad codes. Whether an activation device (including an RF interface or a transponder reader for Access Control) sends an activation or deactivation message to its associated partition depends on the state of its RF-zone when the client acts: if this area was already active because its partition had previously been armed by another activator, the control unit reads the area of the activator as ARMED and so sends a DISARM instruction to the relative partition. This is true even if the user actually wanted to arm them because he or she was not aware that the zone (and therefore the relative partitioning) where the activator was configured was already armed. This is why when you pass the transponder key a second time, the control unit now arms the partition which it previously considered disarmed.