That's most certainly caused by GarryG changing some of the NewGRFs recently: viewtopic.php?p=1259758#p1259758Argus wrote: 13 Apr 2023 12:01 I ran into a problem.
It was probably caused by the fact that we do not have exactly the same versions of the objects. Some objects may have been moved and changed, although the version still reports as compatible.
From now on it is everywhere on both coasts
When I saw this I was like

Either you delete the "rock objects" yourself or you "roll back" to the version of the AuzWaterObjects.grf that was used at the creation of the scenario, which is shown in the NewGRF options as "Auz Water Objects V15" and "Auz Water Objects Add Ons V9"
This "version hell" is exactly what I meant with "realiable" earlier.
There is an option to show all the available NewGRFs that are available, not just the latest version, but I forgot how to switch that, as it is not default - but it was the response of some experienced user to some of my other threads.