Adding a datapoint to this:
I see 2 seats on SAA that are available on UA, AP and ANA, but of course they aren't showing up on LM. I've now written to LM support will see where it goes. This seems like another silent devaluation by LM, between the lack of mixed cabin awards, no LH F, no long connections and now this, it is just so risky with LM. Quite disappointing.