Tom Hoheisel
Comments
Armor and off hand items were randomly repaired fully and never encountered any more damage with no repair to main hand pick. Next try was with main hand pick only item in inventory with mending, still no repair and all exp orbs going to experience level.
Next try with another pick with mending only enchantment and no other mending items in inventory. Used pick to create damage then tried on coal. No repair, all exp orbs went to experience level.
It seems the issue is a corrupt world or related to pre-existing worlds. Started new world and mending does repair main hand item. Problem remains in existing world.