Hi. The cause of the problem is CSS animation that is applied to the Header. Not too successful developer solutions. This code solves the problem.
#sp-header {
animation: none !important;
}
Note for Team: Guys, this animation should be removed from HU template at all. It is absolutely not suitable for use. We have to add this dropping code each time on each new website with HU 2.
I wrote about it even at the stage of alpha beta testing. But the developers did not hear me.
If there is a need somthing using as animation there, it's better transform and transition, but not animation.
Because when using animation, the Header begins to flicker when scrolling, on the pages of many third-party components with which you have not been tested it.