I just noticed this when I looked up the recipe for Yellorium Ore (from Big Reactors). 2 Yellorium Dust (from crushing two ingots) can be put in the Combiner with liquid stone to produce an ore block. I think by default this is fine except that with AOBD mod installed (Another One Bites the Dust), Mekanism's 5x ore processing gets to be used for all ores. I notice all the other recipes for turning dusts into an ore block in the Combiner use 8 dusts. Perhaps Yellorium needs to be changed to be 8 as well.

Obsidian is also a potential problem, I believe you can get 5 obsidian ingots out of one block of obsidian if you run it through the 5x chain, but it only takes 4x dust to make a block.

WHYYYYYY DID U REPORT TEH GLITCH U FRICKIN..... breaks down into a bunch of conflicting emotions

ErogenousBeef (Big Reactors) added the recipe to the combiner, but his intention was an 8-dust recipe, not a 2-dust recipe. He has stated that the next BR release will have the updated combiner recipe.

I guess this isn't a Mekanism issue then