Minecraft: 1.12.1
Schematica version: 1.8.0.164
Lunatrius-Core: 1.2.0.41
Worldedit Version: 6.1.8
Forge: 14.22.1.2478
Issue: Concrete blocks don't appear properly within the schematic (see screenshots)
Reproducable steps:

Get afformentioned Mods, make a schematic file with concrete and try using it with schematica.

The game will show different blocks.

Edit: Forgott to mention this is on a SMP server. (Public) but same bug appears in SSP)
2nd edit: I'm not sure if it's an issue with worldedit which makes the schematics or with schematica.
(Sorry if I posted it wrongfully here in advance)

Here ya go.
Edit: Suspecting it's an issue with minecraft itself. I just did 3 hours of testing, mcedit, worldedit (mod and server plugin) Won't save the schematic properl..
floor.zip

Can you attach the affected schematic to this issue? (You may need to zip it first)

The schematic does not contain a block mapping. Currently only Schematica creates schematics that are compatible across different worlds/saves.