UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36

Steps to reproduce the problem:
1. Using Python 2.7, Selenium 3.x and ChromeDriver 2.43
2. Launch Chrome (WebDriver) with "headless" and "user-data-dir" arguments (see comments for source example)
3. Navigate to a page that would normally have at least one thing cached (such as http://www.example.com/)

What is the expected behavior?
A Default/Cache directory is created and contains cached items from the page navigated to in headless mode.

What went wrong?
There is no Default/Cache directory when "headless" is used but if you remove that argument then there is. I think then that this is an issue with headless mode Chrome.

Did this work before? N/A 

Chrome version: 70.0.3538.77  Channel: stable
OS Version: 16.04.5 LTS
Flash Version: 

Here's some Python 2.7 source you can use to verify with Selenium 3.x and ChromeDriver 2.43:

from selenium import webdriver
options = webdriver.ChromeOptions()
options.add_argument('headless')  # remove this and Cache works
options.add_argument('user-data-dir=/home/ubuntu/chrome')
chrome = webdriver.Chrome(chrome_options=options)
chrome.get('http://www.example.com')
chrome.quit()