I had a bug before with mod, it had something to do with another mod having priority over this one, and that caused the solidified remains to not be craftable in the chem plant. I did find a work around for it though, at the cost of achievements.
Typing in /c game.player.force.technologies['compression-tech-2'].researched=false in the command bar will un-research the solidification tech. Researching it again should bring back the crafting option.
As far as I know it's because of mod incompatibility.
I have been considering changing the back-end name of my recipes, items and entities to include the modname in them to make them compatible with any mod.