Post-grid columns in admin mode

Hello.

When logged-in as admin, i see the post-grid as one column instead of the three-column it should be. (view page and edit page) This happens only on my MacBook, on PC and iMac everything looks fine. I use Chrome on all devices.

Also when logged out, everything is as it should.

Example: https://imgur.com/a/s7YEH4F

The page I need help with: [log in to see the link]