diff --git a/src/option.c b/src/option.c
index a804dd8..bf253a4 100644
--- a/src/option.c
+++ b/src/option.c
@@ -7931,6 +7931,7 @@
 	    // recursively, to avoid endless recurrence.
 	    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname,
 		    value_changed || syn_recursive == 1, curbuf);
+	    curbuf->b_flags |= BF_SYN_SET;
 	    --syn_recursive;
 	}
 #endif