Dorico doesn’t allow multiple instances of the same articulation, or conflicting articulations on the same note. And since tied notes are considered one note in Dorico, the same applies for these.
However - you can choose wether you want to place the articulation on the first or last note of the tie chain.
You’ll find options for this in the properties panel in Engrave mode.
You can also set a global default in the ‘Articulations’ section of ‘Engraving Options’.
