I would say so. Either something broke and they don't care enough to mend it, or they intentionally turned it off. But it would seem clear they only offer it to those who care enough to ask about it.

It is similar to the "waitlist" process on longhaul. Even on flights with plenty unsold seats they don't pubslish any U, and only offer awards/upgrades to those who knows to waitlist. It would seem they are trying to make things so difficult in hope get top tier members forfeit their vouchers and pay for revenue tix.