diff --git a/common/state.c b/common/state.c
index ed9654d092..93107114ff 100644
--- a/common/state.c
+++ b/common/state.c
@@ -124,7 +124,10 @@ static void st_tree_node_add(st_tree_t **nptr, st_tree_t *sptr)
 	*nptr = sptr;
 }
 
-/* remove a variable from a tree */
+/* remove a variable from a tree
+ * except for variables with ST_FLAG_IMMUTABLE
+ * (for override.* to survive) per issue #737
+ */
 int state_delinfo(st_tree_t **nptr, const char *var)
 {
 	while (*nptr) {
@@ -141,6 +144,11 @@ int state_delinfo(st_tree_t **nptr, const char *var)
 			continue;
 		}
 
+		if (node->flags & ST_FLAG_IMMUTABLE) {
+			upsdebugx(6, "%s: not deleting immutable variable [%s]", __func__, var);
+			return 0;
+		}
+
 		/* whatever is on the left, hang it off current right */
 		st_tree_node_add(&node->right, node->left);