The process of obsoleting old assets is broken in the current version of Trainz. In this case the original creator has updated the library without also updating all the assets that use the library. The system should refer only to the latest version of the library, but it isn't working properly.
Ensure you have the latest version of the library - <kuid2:19691:100011:2> Tb Grass Library. Remove <kuid2:19691:100011:1> Tb Grass Library and <kuid:19691:100011> Tb Grass Library from your database. They might be listed as obsolete, but that is not sufficient: make sure they are
deleted.
The second fix makes them technically correct, although it is likely not necessary. The references to the library in config.txt should be to the latest version. Most of these references are inside the mesh table:
Code:
mesh-asset <kuid2:19691:100011:2>
and the other is inside the kuid table
Note that this fix is for reported faults - problems with disappearing items or white blotches are due to something else.