diff --git a/apisix/core/config_util.lua b/apisix/core/config_util.lua
index 7e57ed402fd8..7313e0116ad2 100644
--- a/apisix/core/config_util.lua
+++ b/apisix/core/config_util.lua
@@ -114,7 +114,7 @@ function _M.fire_all_clean_handlers(item)
         clean_handler.f(item)
     end
 
-    item.clean_handlers = nil
+    item.clean_handlers = {}
 end
 
 
diff --git a/apisix/upstream.lua b/apisix/upstream.lua
index 0ff82fea856a..d8e3f3a98750 100644
--- a/apisix/upstream.lua
+++ b/apisix/upstream.lua
@@ -83,7 +83,7 @@ _M.set = set_directly
 local function release_checker(healthcheck_parent)
     local checker = healthcheck_parent.checker
     core.log.info("try to release checker: ", tostring(checker))
-    checker:clear()
+    checker:delayed_clear(3)
     checker:stop()
 end
 
diff --git a/t/node/healthcheck-leak-bugfix.t b/t/node/healthcheck-leak-bugfix.t
index d3ada8c171f7..1caf5d348abf 100644
--- a/t/node/healthcheck-leak-bugfix.t
+++ b/t/node/healthcheck-leak-bugfix.t
@@ -31,8 +31,8 @@ __DATA__
     local new = healthcheck.new
     healthcheck.new = function(...)
         local obj = new(...)
-        local clear = obj.clear
-        obj.clear = function(...)
+        local clear = obj.delayed_clear
+        obj.delayed_clear = function(...)
             ngx.log(ngx.WARN, "clear checker")
             return clear(...)
         end