diff --git a/src/regexp.c b/src/regexp.c
index 229f6ef..375731c 100644
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -2543,6 +2543,7 @@
 	list_free(list);
 	return NULL;
     }
+    ++list->lv_refcount;
     return list;
 }
 #endif
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 61c9cb3..a137aa5 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -881,6 +881,12 @@
   call assert_equal([], submatch(1, 1))
 endfunc
 
+func Test_submatch_list_concatenate()
+  let pat = 'A\(.\)'
+  let Rep = {-> string([submatch(0, 1)] + [[submatch(1)]])}
+  call substitute('A1', pat, Rep, '')->assert_equal("[['A1'], ['1']]")
+endfunc
+
 func Test_substitute_expr_arg()
   call assert_equal('123456789-123456789=', substitute('123456789',
 	\ '\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)',
diff --git a/src/version.c b/src/version.c
index 36416ef..cf7de76 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1621,
+/**/
     1620,
 /**/
     1619,