This is a bug that seems to have been around for a while and is still present in V12, but here’s the best solution I’ve found so far to make your automations follow your track’s events:
Use the Edit > Range > Delete Time function, according to the Nuendo 12 Operation Manual (page 271) and in the Steinberg Help website.
In my case, I needed to move all the tracks to the beginning of the project window. Instinctively, I selected all the tracks and did an Edit > Move > Events to Origin and realized that the automations didn’t follow.
What I did instead was to first select the range in the ruler that I wanted to delete from the project window, then did an Edit > Range > Delete Time and voilà!
All the tracks and their automations were moved together as expected.
This is a huge time-saver, especially when working with Dolby Atmos objects, since there can be up to 128 Atmos objects in a project, and each Atmos object uses one track, each of which can have several automation tracks. Do the math.