I'm working in Premiere 23.1.0 with clips that have 4 channel audio mapped to mono. Whenever I batch create proxies from within Premiere Pro, the clips are changed to adaptive. It used to be that Premiere had a bug where the first clip in the batch was mysteriously changed to adaptive. But now the entire batch changes to adaptive. This seems like a bug. I have to remember to modify audio to change everything back to mono.
Also - I would love someone to point to a resource that explains the advantage of having clips mapped to adaptive. It's a mysterious feature to me!