I was in the process of Minetweaking my instance when I noticed that block forms of gems, ingots, as well block form of Electrotine weren't craftable. After adding block recipes I looked through JEI and found that each of the blocks were uncraftable into their respective components. However, when I put each of those blocks into any crafting table, 9 respective components of the inputted block show up in the crafting GUI. Upon confirming crafting operation, the instance crashes (and loads without issues).

).

This issue has been fixed recently iirc. Not sure if an update has been pushed yet.

These issues were fixed when a JEI plugin was added in 7ffe62e.