Due to flaws the previous changes to the configuration system combined with some bad lines in the experience.config that I mistakenly recommended, herbalism was not granting experience in most cases, as it was marking newly planted crops and such as player placed no exp granting blocks, rather than ignoring them as it should.
block types now are evaluated in 3 steps:
1: Explicit Name i.e. ("Crops|4", "Crops|0"), Which is the material name then data value
2: "friendly name" i.e. ("Crops_Ripe", "Crops_Ungrown"), Which is a typically data valueless name, some of which I make up in mcMMO, but most of which are just the Material name
3: Wildcard name i.e. ("Crops|*") Which is any block with that block value, regardless of data value
In order to be sure herbalism grants exp for you once again, make sure your configuration for herbalism looks similar to this:
https://github.com/mcMMO-Dev/mcMMO/blob/master/src/main/resources/experience.yml#L151
In terms of which blocks are listed there. Specifically, there should be no blocks marked "ungrown"
When a player reaches a certain (configurable) threshold value of total
XP earned in a specific skill, his earned XP in this skill will be
decreased.
Depending on how far the player has exceeded the threshold value, his
XP will decrease more. After the (configurable) time interval of 10
minutes, the registered data will be cleared and the player can earn XP
as normal again.