Prior to 18w06a, smelting cactus into cactus dye gave 0.2 xp per cactus. From 18w06a to 18w14a, cactus was not smeltable at all (see MC-124923).

Since 18w14b however, smelting cactus into cactus dye gives 1 xp per cactus, which is significantly more than before.

This is equivalent to the xp given by smelting gold ore, nether gold ore, diamond ore, and emerald ore. This does not seem like an intended game mechanic, and it makes cactus xp farms very fast.

Also, in Bedrock Edition, cactus dye still only gives 0.2 xp per cactus, indicating that this was an oversight when smelting recipes were introduced.

Videos

• 18w05a: Minecraft 18w05a 2021-01-01 22-34-30.mp4
• 18w14b: Minecraft 18w14b 2021-01-01 23-05-32.mp4
• 20w51a: Minecraft 20w51a - Singleplayer 2021-01-01 23-20-00.mp4