Fix implementation error for manually managed timers

timer.lua

@@ -59,10 +59,12 @@ return {
   update = function(delta)
     local expired = {}
     for timer in pairs(timers) do
+      if not timer.manual then
         if timer:update(delta) then
           expired[timer] = true
         end
       end
+    end
     for timer in pairs(expired) do
       timers[timer] = nil
     end