When a villager gives a discount or increases prices, these price changes vary drastically. When in combination with hero of the village, the villager could discount and increase prices at the same time! This happens with practically all discounts, and applies to all professions. Assuming the prices were supposed to double, it would be expected for the cleric to trade 64 rotten flesh for an emerald, and 2 emeralds for 2 redstone.

To reproduce, spawn 2 villagers and place down a brewing stand and grindstone. Punch both villagers once. The cleric's first trade will increase by 6.25%, while its second trade will increase by 200%. The masons first trade will increase by 20%, while its second trade will increase by 200%. (Under the following context, delta means "change in") The cleric's delta second trade is 32 times worse than its delta first trade, while the mason's delta second trade is 10 times worse than its delta first trade. This logic breaks even more in combination with the hero of the village effect, causing the first trade to be discounted, while the second trade is more expensive.