It can be a bit dangerous that the Alternative text that has been entered in the score is missing in the parts. It may lead to lots of mistakes and demands a kind proof reading that you don’t expect should be needed.
Other properties behave as you expect them, (Starts voice, Laissez vibrer tie and so on) but not this one. It is a bug or is it intended and why?
Just finished a big project in Dorico 3, great update, thanks!
Many properties are currently layout-specific. With the object selected, you need to go Edit > Propagate Properties. Many of us have assigned Propagate Properties to a keyboard shortcut because we use it so frequently. Note that it can be used with multiple items (or everything in a score) selected.
It’s very flexible but not at all automatic, but it’s a stopgap measure that will eventually be replaced with a better solution. Do search the forum for “Propagate Properties” and you’ll see it’s been discussed at length.