Slur is not displayed correctly

The slur overwrites the stems (see the example in appendix).
After “beam together” (which you don’t want at this point) it is displayed correctly.

Cross-staff slurs cannot be automatically routed around all potential collisions; you should expect to have to make some adjustments in Engrave mode for such slurs.

Thank you for the info, so I have to live with it.

No, you drag the handles in order to fix it manually.

That is what I meant by that.