Obsessive patience paid off
I have spent the whole weekend figuring out how to get to Zurich on Friday on a saver reward ticket. I was checking once an hour. Finally, one flight segment that had the 'phantom' availability in O on LH after checking maybe 20 times, all of a sudden it cleared and I was able to book seats via the LH recloc on the LH site. Success! But what a waste of time lol