commit https://github.com/vim/vim/commit/1436d8d51cce114be56209924fc71376407e5bad Author: Bram Moolenaar <Bram@vim.org> Date: Mon Jul 11 22:41:15 2016 +0200 patch 7.4.2026 Problem: Reference counting for callbacks isn't right. Solution: Add free_callback(). (Ken Takata) Fix reference count.

--- a/src/ex_cmds2.c
+++ b/src/ex_cmds2.c
@@ -1121,8 +1121,7 @@ remove_timer(timer_T *timer)
     static void
 free_timer(timer_T *timer)
 {
-    vim_free(timer->tr_callback);
-    partial_unref(timer->tr_partial);
+    free_callback(timer->tr_callback, timer->tr_partial);
     vim_free(timer);
 }