Slurs on staff break

Even in Dorico 3.5 I’m getting this default slur appearance :

Is this the expected behaviour or am I missing something?

This has changed in the last update but doesn’t reflect in previous projects. Maybe the change will fix this. Does this happen in a new project? If so, you might want to check out this post to perform these changes in your project:
https://www.steinberg.net/forums/viewtopic.php?f=246&t=189119

Flat slurs have a much simpler collision avoidance algorithm than curved slurs, so unfortunately this is their current behaviour at system breaks. You can either switch the slur’s curvature type to curved, or manually adjust the slur end points in engrave mode.