I ordered literally as the price changed on July 22nd. Seriously. 15 minutes getting distracted cost $1,000. At that time, the order page said "Est. Delivery: October." When I got kicked back to a refreshed order page because the price changed, the est. delivery was gone. I ordered and then promptly completed my profile the same day. No EDD in the account. A day or two later, the order page said "Est. Delivery: November," but my SA said I was still October. Then, I got an EDD of Sept. 19th-30th for a day, which vanished the next. I've been alternating between nothing and "December" since.
I've noticed from people's sigs in the forum that anyone with 7/21 order dates or earlier that don't have a date range are seeing "October." Those with order dates of 7/22 or later (myself) are seeing "December." So, what happened to November? Supposedly, if I ordered right now almost 3 weeks later, I'd still have exactly the same EDD! I'm guessing these are just odd placeholders, and that as we get into September they'll change to actual date ranges.
EU is supplied by China for the Model Y, so that's not it.