diff --git a/mods/MAPGEN/mcl_mapgen_core/init.lua b/mods/MAPGEN/mcl_mapgen_core/init.lua
index e75bcacb4..e5d33713c 100644
--- a/mods/MAPGEN/mcl_mapgen_core/init.lua
+++ b/mods/MAPGEN/mcl_mapgen_core/init.lua
@@ -4,6 +4,8 @@ local registered_generators = {}
 local modname = minetest.get_current_modname()
 local modpath = minetest.get_modpath(modname)
 
+local RANDOM_SEED_OFFSET = 959 -- random constant that should be unique across each library
+
 --
 -- Aliases for map generator outputs
 --
@@ -426,23 +428,22 @@ if mg_name == "v6" then
 end
 
 -- This should be moved to mcl_structures eventually if the dependencies can be sorted out.
-mcl_mapgen_core.register_generator("structures",nil, function(minp, maxp, blockseed)
+mcl_mapgen_core.register_generator("structures", nil, function(minp, maxp, blockseed)
 	local gennotify = minetest.get_mapgen_object("gennotify")
-	local has = false
-	local poshash = minetest.hash_node_position(minp)
 	for _,struct in pairs(mcl_structures.registered_structures) do
-		local pr = PseudoRandom(blockseed + 42)
 		if struct.deco_id then
 			for _, pos in pairs(gennotify["decoration#"..struct.deco_id] or {}) do
-				if struct.chunk_probability == nil or (not has and pr:next(1,struct.chunk_probability) == 1 ) then
+				local pr = PcgRandom(minetest.hash_node_position(pos) + blockseed + RANDOM_SEED_OFFSET)
+				if struct.chunk_probability == nil or pr:next(1, struct.chunk_probability) == 1 then
 					mcl_structures.place_structure(vector.offset(pos,0,1,0),struct,pr,blockseed)
-					has=true
+					if struct.chunk_probability then break end -- one (attempt) per chunk only
 				end
 			end
 		elseif struct.static_pos then
-			for _,p in pairs(struct.static_pos) do
-				if vector.in_area(p,minp,maxp) then
-					mcl_structures.place_structure(p,struct,pr,blockseed)
+			local pr = PcgRandom(blockseed + RANDOM_SEED_OFFSET)
+			for _, pos in pairs(struct.static_pos) do
+				if vector.in_area(pos, minp, maxp) then
+					mcl_structures.place_structure(pos, struct, pr, blockseed)
 				end
 			end
 		end