[Edi]

It's possible the #leper mod command is linked to the wrong icon. The leper icon is the one e.g. Eater of the Dead has (a diseased head different from the disease affliction head), while Harvester of Sorrows, Poison Golem and Mabakiel all have the reaper icon (a scythe).

So that's a relatively easy fix to put in and I must fix the manual accordingly. I went by what Johan told me, but I guess there was some confusion.