diff --git a/src/evalbuffer.c b/src/evalbuffer.c
index b7aac9a..8a6c52d 100644
--- a/src/evalbuffer.c
+++ b/src/evalbuffer.c
@@ -88,6 +88,8 @@
 
     if (avar->v_type == VAR_NUMBER)
 	buf = buflist_findnr((int)avar->vval.v_number);
+    else if (in_vim9script() && check_for_string_arg(avar, 0) == FAIL)
+	return NULL;
     else if (avar->v_type == VAR_STRING && avar->vval.v_string != NULL)
     {
 	buf = buflist_findname_exp(avar->vval.v_string);
diff --git a/src/testdir/test_vim9_builtin.vim b/src/testdir/test_vim9_builtin.vim
index 766a5bc..7897db0 100644
--- a/src/testdir/test_vim9_builtin.vim
+++ b/src/testdir/test_vim9_builtin.vim
@@ -133,7 +133,7 @@
 enddef
 
 def Test_balloon_split()
-  CheckFeature balloon_eval
+  CheckFeature balloon_eval_term
 
   assert_fails('balloon_split(true)', 'E1174:')
 enddef
diff --git a/src/version.c b/src/version.c
index 435efeb..8e04e9a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2665,
+/**/
     2664,
 /**/
     2663,