Sticky navigation shows only half of my split menu

I made a split menu, using Primary navigation (left) and secundair navigation (right) with a logo in the middle.
Now the Sticky menu shows just the main menu (the 3 items of main menu).
https://zorgelooservennl.hosting-cluster.nl/
Scroll to see the Sticky navigation with only three items.
Is there a solution to include the secundair menu in the Sticky one?
Thank you for your time!
Moon