Cobblestone and Nether Quartz mistakenly show up in materials list

[shazean]

When I add items to the queue to craft, cobblestone and nether quartz consistently show up in the materials list, even though they're not related.

Sometimes when I craft things on the queue, the quantity of cobblestone and nether quartz increases, though not always? And sometimes the nether quartz changes to nether quartz ore instead.

When I had a larger list of items queued and crafted some of them, sometimes the cobblestone and quartz disappeared, although I'm not totally sure when.