diff --git a/engine/src/flutter/runtime/dart_vm.cc b/engine/src/flutter/runtime/dart_vm.cc
index 46cbfa7dae..8dc3ab7db8 100644
--- a/engine/src/flutter/runtime/dart_vm.cc
+++ b/engine/src/flutter/runtime/dart_vm.cc
@@ -54,7 +54,8 @@ static const char* kDartAllConfigsArgs[] = {
     "--enable_mirrors=false",
     "--background_compilation",
     "--lazy_async_stacks",
-    "--mark_when_idle",
+    // 'mark_when_idle' appears to cause a regression, turning off for now.
+    // "--mark_when_idle",
     // clang-format on
 };