I flew EUG-IND in first class in June and got repeated emails to choose my meal, starting 5 days beforehand. I went and chose one (out of 5 options) and still the emails arrived every day: "Pre-order your meal!"
I am scheduled to fly ORD-LHR Polaris tomorrow and it suddenly occurred to me that I hadn't gotten a single email about choosing a meal. So I went to the United site and found my flight, and it offered me a selection of 4 dinners: steak, turbot, tortellacci, and spicy Thai chicken — but the steak and the tortellacci (in other words, the ones I would have chosen) are sold out. Nothing mentioned about breakfast.
I conclude that their procedure remains a bit erratic.