Minecraft 1.12.2
Magneticraft_1.12-2.7.0-dev.jar
ThermalFoundation-1.12.2-2.6.3.27-universal.jar

Issue: Crafting 9 lead ingots into a block creates a Magneticraft Lead Block aka magneticraft:storage_blocks:1 #8030/1 with oredict blockGalena that can't be crafted back into lead ingots or ore dictionary converted to a Thermal Foundation Lead Block aka thermalfoundation:storage:3 with oredict blockLead

Workaround: I was able to disable this recipe in a modpack using a crafttweaker script and it appears to still be possible to craft double and heavy lead plates using ingots.