The tag HandDropChances is "[2.0f, 0.0f]" instead of "[0.085f, 0.085f] on certain mobs updated directly from 1.8.9 or before to 20w30a. Similarly, the tag ArmorDropChances is "[2.0f, 2.0f, 2.0f, 2.0f]" instead of "[0.085f, 0.085f, 0.085f, 0.085f]". This only seems to effect certain mobs. Related to MC-195743
Please merge this in MC-195743.