Connected via Matter. I configure the same way as the Tapo/Kasa dimmers, setting power-on level to full (not previous level). No matter what level I set in automation, it always comes on full. If I set to some other level in hardware, it starts at that level both by activating switch and automation. Updated firmware, no change.
Found the solution. The default power can be set to 100, and then the automation requires two actions. Turn the light on, add a 500ms delay, then turn it on again at desired level. Going from 100% to 10% cannot be detected, looks like it comes on at 10.