Brand new Late 2015 iMac startup sequence: Is this normal?

[Tymbo]

Forgive my messy background, lol, but the way my iMac starts up looks so weird to me...

Apple logo appears. (normal)
Status bar appears below logo. (normal)
Status bar progresses. (normal)
Everything goes black. (?)
Everything comes back but flashes black again. (?)
Everything comes back right as it ends, and the Apple logo makes it onto the desktop for a brief second. (??)

 

[Malus120]

Yes I believe so. At least I hope so as my 5K iMac's been doing that for the last year

 

[Tymbo]

I hope you're right. But it really should not do that!