Villager Trade Lock after transformation

In Minecraft 1.16.5 Spigot when I try to transform the same zombie villager more than 1 time, the trade with the villager gets lower and lower until the change is for example 1 carrot for 1 emerald. Why in Paper If I transform two times (or more) the same zombie villager with the second transformation the value of the trades remain the same? At the first transformation, the trades go down but then they don’t go down anymore. Any idea for this problem? Thanks in advance for the reply.

The Paper Project aims to fix bugs among other things, and villager’s trades decreasing in cost after every transformation is a confirmed bug. The trades should only go down in price once, as happens on a paper server.