Fixed block does not stretch to screen width on ipad. What is the problem?

Question

css

There is a site: anatomyclub.su on which, when scrolling at the bottom, the cap sticks to the top of the screen.
The header runs the full width of the page.

Absolutely on all devices and browsers everything is fine, except for the iPad. It doesn't matter which browser is safari or chrome, everywhere the header when scrolling down stretches to 100% of the screen width:

Tried:

.sticky.active{
width: 100%;
width: 100vw;
min-width: 100%;
min-width: 100vw;
right: 0
}

Nothing helps.