Particle P2 Need to Reset To Run Program

I Write code to test every GPIO Properly Work, so in Code all GPIO become high and low one by one, all GPIO connected to external LEDs .

But Every time when Particle P2 power Off and Then give it power to on , It Need to push Reset button To Run Program.

That should not occur. I’d take a closer look at the 3.3V power supply. It may be rising too slowly, causing the device to not boot correctly.