Unit powers on after Plugging power cable without pressing power button

Follow up to my previous post of wich 1 of the 2 units when i turn it on , the led sequence wont starts. Ive found out yesterday, after turning off the unit by pressing the power bottun then hit the screen YES, i`ve unplugged the power cable waitted a bit , put it back on the unit turns on without hitting power button to power up, then the led sequence works in that case. But the unit is not suppose to act this, i hope i was able to explain my situation clearly Waiting for ur help & response

thank you