In VGC 2021 series 9, auto down leveling (at least) doesn't seem to work anymore, as showcased in the replay below.
Also, only 3 mons can be picked at preview (shown in the replay too)
https://replay.pokemonshowdown.com/gen8vgc2021series9-1335319803-7lw0dacszn4btgh59kv87rard21r3jlpw
BUG STATUS...