diff --git a/src/browser/renderer/atlas/CharAtlasUtils.ts b/src/browser/renderer/atlas/CharAtlasUtils.ts
index b196b37301..be92727a33 100644
--- a/src/browser/renderer/atlas/CharAtlasUtils.ts
+++ b/src/browser/renderer/atlas/CharAtlasUtils.ts
@@ -16,7 +16,7 @@ export function generateConfig(scaledCharWidth: number, scaledCharHeight: number
     cursor: undefined,
     cursorAccent: undefined,
     selection: undefined,
-    ansi: colors.ansi
+    ansi: [...colors.ansi]
   };
   return {
     devicePixelRatio: window.devicePixelRatio,