Got it. Helpful context. I appreciate it. I went straight to replacing a part that's not broken. All the best.Well, to be fair, the stock HID system was short-lived (3 years), particularly on 4 cylinder Outbacks (looks like 2017 was it for those). Pretty sure the LED projectors they started using in 2018, just like probably all OE LED headlights, are in fact not serviceable. But the HID housing is unique - an experienced tech should be able to visually ID that right away.
They would have realized their mistake as soon as it came time to install that LED housing - the harness connectors would not match up. So you wouldn't have been charged, just inconvenienced.