diff --git a/builtin/game/async.lua b/builtin/game/async.lua
index d184440c9..f85864649 100644
--- a/builtin/game/async.lua
+++ b/builtin/game/async.lua
@@ -34,7 +34,7 @@ if core.async_job_methods then
 
 	local dummy = function() end
 	function core.async_job_methods:cancel()
-		return self:get_id() == self:replace(dummy, dummy)
+		return self:get_id() == self:replace(dummy, dummy):get_id()
 	end
 
 	core.async_job_methods = nil
diff --git a/games/devtest/mods/unittests/async_env.lua b/games/devtest/mods/unittests/async_env.lua
index fb081614c..7d222c148 100644
--- a/games/devtest/mods/unittests/async_env.lua
+++ b/games/devtest/mods/unittests/async_env.lua
@@ -212,7 +212,6 @@ local function test_async_job_replacement(cb)
 	local job = core.handle_async(function(x)
 		return x
 	end, function(ret)
-		print(ret)
 		cb("Replaced async callback still run")
 	end, 1)
 	local newjob = job:replace(function(x)
@@ -223,7 +222,7 @@ local function test_async_job_replacement(cb)
 		end
 	end, 2)
 	if job:get_id() ~= newjob:get_id() then
-		cb("core.replace_async sanity check failed")
+		cb("AsyncJob:replace sanity check failed")
 	end
 
 	job = core.handle_async(function(x)
@@ -243,7 +242,7 @@ local function test_async_job_replacement(cb)
 			return cb("Wrong async value passed to old handler")
 		end
 
-		newjob = job:replace(id, function(x)
+		newjob = job:replace(function(x)
 			return -x
 		end, function(new_ret)
 			if new_ret ~= -2 then
@@ -252,10 +251,10 @@ local function test_async_job_replacement(cb)
 			cb()
 		end, 2)
 		if job:get_id() == newjob:get_id() then
-			cb("core.replace_async replaced a completed job")
+			cb("AsyncJob:replace replaced a completed job")
 		end
-		if id:cancel() then
-			cb("core.relpace_async canceled a completed job")
+		if job:cancel() then
+			cb("AsyncJob:replace canceled a completed job")
 		end
 	end, 1)
 end
diff --git a/src/script/lua_api/l_async.cpp b/src/script/lua_api/l_async.cpp
index 8c0e52f8f..e2c8ec7be 100644
--- a/src/script/lua_api/l_async.cpp
+++ b/src/script/lua_api/l_async.cpp
@@ -77,7 +77,7 @@ void LuaAsyncJob::Register(lua_State *L)
 	lua_getglobal(L, "core");
 	luaL_getmetatable(L, className);
 	lua_getfield(L, -1, "__index");
-	lua_setfield(L, -2, "async_job_methods");
+	lua_setfield(L, -3, "async_job_methods");
 }
 
 const char LuaAsyncJob::className[] = "AsyncJob";