When pasting a structure it will sometimes change some blocks; sand to sandstone and also gravel to sandstone.
Check our Schematic server for issue.

Using:
minecolonies-1.12.2-0.10.150-ALPHA-universal.jar
Which uses:
\memory_repo\com\structurize\structurize\1.12.2-0.10.42-ALPHA\structurize-1.12.2-0.10.42-ALPHA.jar

Closed in favor of: minecolonies/issues/3326