It looks very strange, but I can't figure out why emoticons and custom fonts can't be screenshotted in headless mode? I am using selenium with these presets:
chrome_options.add_argument("--disable-gpu")
chrome_options.add_argument("--no-sandbox")
chrome_options.add_argument("--headless")
chrome_options.add_argument("window-size= 3840, 2160")
Important, the problem arose on ubuntu server 22.04, everything works correctly on ubuntu desktop 20.04. I just reinstalled the script on ubuntu 20.04 and everything worked. Maybe the updated version of ubuntu 22.04 has not yet fixed this bug
original: https://i.stack.imgur.com/nfFoy.png
screenshot in headless mode: https://i.stack.imgur.com/t4PKp.jpg