diff --git a/internal/bundler_tests/bundler_default_test.go b/internal/bundler_tests/bundler_default_test.go
index d272cf5eb38..2eb614a7a19 100644
--- a/internal/bundler_tests/bundler_default_test.go
+++ b/internal/bundler_tests/bundler_default_test.go
@@ -7493,8 +7493,8 @@ func TestManglePropsKeyCommentMinify(t *testing.T) {
 				x[/* @__KEY__ */ '_mangleThisToo'] = 2
 				x['_doNotMangleThis'] = 3
 				x([
-					` + "`" + `foo.${/* @__KEY__ */ '_mangleThis'} = bar.${/* @__KEY__ */ '_mangleThisToo'}` + "`" + `,
-					` + "`" + `foo.${/* @__KEY__ */ 'notMangled'} = bar.${/* @__KEY__ */ 'notMangledEither'}` + "`" + `,
+					` + "`" + `${foo}.${/* @__KEY__ */ '_mangleThis'} = bar.${/* @__KEY__ */ '_mangleThisToo'}` + "`" + `,
+					` + "`" + `${foo}.${/* @__KEY__ */ 'notMangled'} = bar.${/* @__KEY__ */ 'notMangledEither'}` + "`" + `,
 				])
 		`,
 		},
diff --git a/internal/bundler_tests/snapshots/snapshots_default.txt b/internal/bundler_tests/snapshots/snapshots_default.txt
index 265928bf67d..be5ce957ea6 100644
--- a/internal/bundler_tests/snapshots/snapshots_default.txt
+++ b/internal/bundler_tests/snapshots/snapshots_default.txt
@@ -3253,8 +3253,8 @@ x = class {
   b: 2,
   _doNotMangleThis: 3
 }, x.a = 1, x.b = 2, x._doNotMangleThis = 3, x([
-  "foo.a = bar.b",
-  "foo.notMangled = bar.notMangledEither"
+  `${foo}.a = bar.b`,
+  `${foo}.notMangled = bar.notMangledEither`
 ]);
 
 ================================================================================
diff --git a/internal/js_printer/js_printer.go b/internal/js_printer/js_printer.go
index e069ffc7eb1..470f9993dd1 100644
--- a/internal/js_printer/js_printer.go
+++ b/internal/js_printer/js_printer.go
@@ -2868,12 +2868,13 @@ func (p *printer) printExpr(expr js_ast.Expr, level js_ast.L, flags printExprFla
 			for i, part := range e.Parts {
 				if mangled, ok := part.Value.Data.(*js_ast.ENameOfSymbol); ok {
 					if replaced == nil {
-						replaced = make([]js_ast.TemplatePart, len(e.Parts))
+						replaced = make([]js_ast.TemplatePart, 0, len(e.Parts))
+						replaced = append(replaced, e.Parts[:i]...)
 					}
 					part.Value.Data = &js_ast.EString{Value: helpers.StringToUTF16(p.mangledPropName(mangled.Ref))}
-					replaced[i] = part
+					replaced = append(replaced, part)
 				} else if replaced != nil {
-					replaced[i] = part
+					replaced = append(replaced, part)
 				}
 			}
 			if replaced != nil {