Admin dashboard lay-out issue

In my media gallery and woocommerce order overview in the right upper corner my navigation shows a wrong lay-out.

I have a multisite.

Site 1 shows the correct lay-out:

Site 2 the wrong lay-out:

I don’t know if there is a direct cause for it. I’ve tried deactivating all plugins with no effect :-(. Also clearing cache, restoring standard theme… no effect.

thanks in advance for your help!