Optima G4 alarm activates on entry?

My Optima G4 panel sets ok on exit when leaving the premises, however on entry the alarm is activated before you can enter its key code. When you view the panel leds 1 and 2 are on and 3 is flashing. Zone 1 has just the entry/exit door on it and a pa button, Zone 2 has three pirs one in the bedroom and 2 in the hallway which should be inhibited but they appear to activate the alarm on entry? Zone 3 has two pirs in other rooms which are not in the E/E route plus a couple of door contacts. All the circuits have been tested seperately for continuity and resistance no problems there. So why does the panel let you set it on exit ok but not isolate it on re-entry ?