You may also find that explicit clefs are added to your score when importing XML files. If you can click on the clef (it turns orange), it is explicit. Delete all of those at the beginning of the score. I also do a to the SAME instrument in Setup for every player (even if it’s been correctly identified). That attaches any specific quirks about that particular instrument correctly (notes out of range, dynamics above staff [vocal staves], etc).
I also find it’s a helpful to [Write|Edit menu]:
+Stems|Remove Forced Stems
This gets everything back to Dorico defaults, so that changes made in the Engraving and Notation Options will be accurately reflected in your score.
You may find otherwise, but these things help me save time overall with XML imports.