diff --git a/docs/changelog.rst b/docs/changelog.rst
index 77d0badd7..5572d17ac 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -106,6 +106,11 @@ consumption to do the same tasks.
 Detailed list of changes
 -------------------------------------
 
+0.42.1 [future]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Fix ambiguous width and private use characters not being rendered when used with variable width text-sizing protocol escape codes
+
 0.42.0 [2025-05-11]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/kitty/screen.c b/kitty/screen.c
index 7891c8a70..a677a93dd 100644
--- a/kitty/screen.c
+++ b/kitty/screen.c
@@ -1323,8 +1323,10 @@ screen_handle_multicell_command(Screen *self, const MultiCellCommand *cmd, const
             if ((s = grapheme_segmentation_step(s, cp)).add_to_current_cell || (wcwidth_std(cp) == 0 && lc.count)) lc.chars[lc.count++] = ch;
             else {
                 if (lc.count) handle_variable_width_multicell_command(self, mcd, &lc);
-                if (wcwidth_std(cp) < 1) lc.count = 0;
-                else { lc.chars[0] = ch; lc.count = 1; }
+                switch(wcwidth_std(cp)) {
+                    case 0: case -1: lc.count = 0; break;
+                    default: lc.chars[0] = ch; lc.count = 1; break;
+                }
             }
         }
         if (lc.count) handle_variable_width_multicell_command(self, mcd, &lc);
diff --git a/kitty_tests/multicell.py b/kitty_tests/multicell.py
index 42ee5d85c..9908faed5 100644
--- a/kitty_tests/multicell.py
+++ b/kitty_tests/multicell.py
@@ -135,6 +135,9 @@ def test_multicell(self: TestMulticell) -> None:
         for x in range(1, 3):
             comb(x, y)
     comb(0, 1)
+    s.reset()
+    multicell(s, 'aüa', scale=2)
+    self.ae(s.cursor.x, 6)
     s = self.create_screen(cols=7 * 7, lines=7)
     multicell(s, 'a', scale=7, width=7)
     for y in range(s.lines):