I managed to find an obscure website that had 3M 8509 for a good price and free shipping. I ordered a tube (I assumed old stock,) but have yet to see it arrive. I recall getting an order confirmation, but can't find that now in my inbox. Maybe it was a scam all along, as 3M doesn't list it.
[on edit] I found the order confirmation by text and they had a shipping status link there. Checking that says as of Oct 6, "Awaiting vessel confirmation. We are coordinating with our shipping partners to secure a spot for your order. This might take 3-4 days."
Maybe it's coming from overseas and they're trying to get that one tube into a container ship coming from some foreign port or maybe from Florida through the Panama canal. Fortunately, I'm not in a hurry to get my windshield installed.
