Using async/await inside for-of loop, memory leak?

Im using await inside for of loop, but it seems that it is causing memory leak.

 let fullItems = [];
 for (let item of items) {
    let transformedItem = transformItem(item);

    let itemGroups = await itemService.getItemGroups(item.id);
    transformedItem.groups = itemGroups.map(transformItemGroup);

    fullItems.push(transformedItem);
  }

Is there something wrong with my loop, or is this issue with babel?

If i change my loop to traditional for loop, I have no issues with memory usage.

My versions:

• babel-cli: 6.18.0
• babel-core: 6.18.0
• babel-preset-env: 1.4.0
• Node: 6.9.3

via devha