Hello,
There is a long-standing issue with artificial harmonics related to how Dorico treats them as a single object.
In Engrave mode, it is not possible to edit the ties independently. Any modification made to one tie is automatically applied to the other.
For example, if I increase the curvature of the upper tie, the lower tie is adjusted in the same way and in the same direction. This makes it impossible to fine-tune their appearance individually, even when different adjustments are needed for proper engraving.
#Thank_you_for_your_attention_to_this_matter 
JM