Probably redundant question

Hi Guys, Newbie here. My buddy does a lot of Solar panels and I have picked up the bug. Working with him we were testing some used 255watt microinverters in full AZ sun. We both timed a lag in energy production at 5 minutes +-. Ya'll already know about this I presume but why is there such a lengthy lag in energy production? I just finished reading your forum about the 'warming' of the panels produced by electron movement and 'short circuiting' of such etc. He has mentioned this lag to me before and he explained that the lag is inherent in the system.....but why?
Comments
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Once the power has been "good" (within voltage specifications, and frequency specs), inverter(s) will turn on. Any "faults" before the GT inverter turns on, resets the timer back to zero.
-Bill