there is no such thing as partner upgrade availability....only Asia Miles can be used to upgrade.

And if anecdotes here are any lesson, it seems like AM/MPC treat upgrades vs straight redemptions from different buckets. Very annoying but that seems to be the case based on a lot of anecdotes here. So it could theoretically be possible a redemption award was visible on BA's website (in which case it will also be available as straight redemption via calling AM/MPC), but NOT as an upgrade redemption. I'm not endorsing this nonsense, but repeating what I think are the facts unfortunately.

The best way to see if they're playing games is to ignore the BA website (which shows phantom availability anyway), and call MPC / AM and ask if they have full redemptions available. Aka not upgrade redemptions. Never have I come across - nor read on here - where partners have availability that AM doesn't. On the contrary, AM/MPC often has inventory that isn't yet released to partners. Either way, your problem can be solved by calling AM/MPC. If they tell you there's availability for a pure redemption - but not available for upgrade - then you have your answer. Two different buckets unfortunately.

They are incompetent a lot of the times, but they don't lie about availability.