NuclearCraft-2.5a--1.12.2.jar
Mincraft 1.12.2
Forge 14.23.1.2556

Rotating any machine will lose all of the contents of the machine in 1.12. Apparently this is because Forge causes all tile entities to be rotatable by default and if you don't support it properly it will cause issues.

Ok, I will have to work out how rotation of tile entities work, but for now, I have just diasbled rotation so that nobody accidentally loses their stuff.

Yep, noticed this myself - will sort it out. This is also 1.10/11.2 bug.