I just had a buyer reach out mentioning he had purchased several LEGO heads that turned out to be double-sided but had expected that they be single-sided based on the listing. Normally it's not an issue for figs with hair, but he's specifically trying to make cowboy/Western style figs with hats, so unless it's a hair+hat combo part, a hat isn't going to cover the back.
I don't know how many fig heads are represented like this in the catalogue, but take this one for example: https://www.brickowl.com/catalog/lego-yellow-worker-male-60374-minifigure-head-recessed-solid-stud-101383
The only indication that it's double-sided is in the top left if you notice the extra photo that shows both sides when viewing from the main catalogue (1st attached pic). But it becomes even less clear when the buyer is viewing it from your store (2nd attached pic). It doesn't even show the other photo.
I'm not sure if there's an easy fix for this unless it's more clear in the part titles, or if there's a way to make the main photo for these the double-sided view.