diff --git a/src/option.c b/src/option.c
index 2356079..2ecdcea 100644
--- a/src/option.c
+++ b/src/option.c
@@ -6029,7 +6029,7 @@
     /* set when changing an option that only requires a redraw in the GUI */
     int		redraw_gui_only = FALSE;
 #endif
-    int		ft_changed = FALSE;
+    int		value_changed = FALSE;
 #if defined(FEAT_VTP) && defined(FEAT_TERMGUICOLORS)
     int		did_swaptcap = FALSE;
 #endif
@@ -7437,7 +7437,7 @@
 	if (!valid_filetype(*varp))
 	    errmsg = e_invarg;
 	else
-	    ft_changed = STRCMP(oldval, *varp) != 0;
+	    value_changed = STRCMP(oldval, *varp) != 0;
     }
 
 #ifdef FEAT_SYN_HL
@@ -7445,6 +7445,8 @@
     {
 	if (!valid_filetype(*varp))
 	    errmsg = e_invarg;
+	else
+	    value_changed = STRCMP(oldval, *varp) != 0;
     }
 #endif
 
@@ -7565,20 +7567,24 @@
 	/* When 'syntax' is set, load the syntax of that name */
 	if (varp == &(curbuf->b_p_syn))
 	{
+	    // Only pass TRUE for "force" when the value changed, to avoid
+	    // endless recurrence. */
 	    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn,
-					       curbuf->b_fname, TRUE, curbuf);
+				       curbuf->b_fname, value_changed, curbuf);
 	}
 #endif
 	else if (varp == &(curbuf->b_p_ft))
 	{
 	    /* 'filetype' is set, trigger the FileType autocommand.
 	     * Skip this when called from a modeline and the filetype was
-	     * already set to this value. */
-	    if (!(opt_flags & OPT_MODELINE) || ft_changed)
+	     * already set to this value.
+	     * Only pass TRUE for "force" when the value changed, to avoid
+	     * endless recurrence. */
+	    if (!(opt_flags & OPT_MODELINE) || value_changed)
 	    {
 		did_filetype = TRUE;
 		apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft,
-					       curbuf->b_fname, TRUE, curbuf);
+				       curbuf->b_fname, value_changed, curbuf);
 		/* Just in case the old "curbuf" is now invalid. */
 		if (varp != &(curbuf->b_p_ft))
 		    varp = NULL;
diff --git a/src/version.c b/src/version.c
index 192b6cd..d3c7316 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    66,
+/**/
     65,
 /**/
     64,