diff --git a/src/nvim/api/win_config.c b/src/nvim/api/win_config.c
index 1f9550a187..9c396bfce1 100644
--- a/src/nvim/api/win_config.c
+++ b/src/nvim/api/win_config.c
@@ -1360,7 +1360,7 @@ static bool parse_win_config(win_T *wp, Dict(win_config) *config, WinConfig *fco
   }
 
   if (relative_is_win || is_split) {
-    if (reconf && relative_is_win) {
+    if (wp && relative_is_win) {
       win_T *target_win = find_window_by_handle(config->win, err);
       if (!target_win) {
         goto fail;
diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index 0369e55a30..1c7f309627 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -11191,6 +11191,9 @@ describe('float window', function()
       local winid = api.nvim_open_win(buf, false, config)
       api.nvim_set_current_win(winid)
       eq('floating window cannot be relative to itself', pcall_err(api.nvim_win_set_config, winid, config))
+      -- Also when configuring split into float.
+      command('split')
+      eq('floating window cannot be relative to itself', pcall_err(api.nvim_win_set_config, 0, config))
     end)
 
     it('bufpos out of range', function()