When using a golden pickaxe to mine iron ore/blocks, gold ore/blocks, lapis ore/blocks, redstone ore/blocks, diamond ore/blocks, or emerald ore/blocks, it does not drop anything. I tested it on most other blocks that are mined with a pickaxe (including silk touch, generated with commands, enchanted, and enchanted beyond normal means) and had no other issues. Appears to only be those 6 ores/blocks. Works on coal, nether gold, and nether quartz.