Not sure why it didn’t set, apart from it’s not milk and there’s nothing milky about oat milk (except the colour?). But I did read that double the milk and you get great chocolate milkshake…
If the oat milk is for vegan diet purposes it’s probably for the best it didn’t work out as butterscotch angel delight has dried milk and butter in it I think.
I tried to make butterscotch angel delight with Minor Figures oat milk last night but it didn't set ☹️