Lag on iPad opening screen

As every normal device, my iPad starts with a black apple logo in a white background.

But after a few while, the apple logo turns white, and the iPad looks like lagging (about 3 sec).

My iPad was bought in a month, without any crashing or JB. I’ve tried restoring my pad but that didn’t work...What should I do?

Device: iPad pro 10.5 64G

Version: ios11.0.3