If you have set the Alarm Panel to Arm 'Away' and while Arm Delay is counting down a PIR Motion Sensors sets off the alarm immediately, this should not occur as the Arm Delay should give you enough time to exit you home or business before the alarm system is fully armed.
If this is happening, narrow down which PIR sensor it is and contact our support team at OSI Go Direct to create a support ticket: https://www.osigodirect.com/contact/
Thank you
OSI Go Direct -Customer Support