Code:
recruit_pool "Kataphracts" 1 0.12 2 0 requires ... and hidden_resource desert or hidden_resource grasland and resource gold
recruit_pool "Kataphracts" 1 0.10 1 0 requires ... and hidden_resource desert or hidden_resource grasland and not resource gold
In desert regions - whether it has gold or not - both of those lines are true so the replenishment rate is actually 0.22. Maybe that is on purpose? I don't know but suspect not: I assume that gold presence should increase recruitment in deserts too.
"gold" regions:

"desert" regions:

"grasland" regions: