MACBOOK PRO Early 2015 lightning-Thunder-like appears when logging in.

[sarahpaez22]

So I have this Macbook Pro Early 2015 the 13" one.. when turning on seems to be fine but after logging in theres a lightning thunder-like appearing on the screen.. has this happen to anyone of you? Am I the only one? I bought it February of this year.
It does not show up everytime.. just randomly. Maybe 8x now.
MAC OS X EL CAPITAL 10.11.6

Here is the link:
https://youtu.be/x_h5zL5O2uM

You would notice at 15 seconds onwards frame.
Is it alarming? I have never experience so far any problem with my mac except that lightning thing.

Thank you in advance..

 

[michelfo]

It's a bit hard to see on the video. Is the whole screen quickly flashing white?

I don't think it's particularly worrisome, as long as it stays predictable and always at the same moment every time it happens. Looks like a small inconsequent glitch in the preparation of the fade-in animation for showing the non-blurred desktop.