The only header layout that shows the offcanvas menu is #6 + #7 + the new #8 and there is no other menu visible.
The other icons you might see there are the menu elements icons, not the offcanvas toggle icon.
Where is the need of 2 main menus? What do you want to achieve?
One solution might to pick the menu layout #1 and set the menu alignment to center (or whatver you want). Then enable the page side area sidebar under page options and put any content inside you want to.
