The official website of a certain AP states that the maximum power is 20dbm, but the available parameter range when configuring max-power in the AP RF view shows as 1-12dbm?
The issue is likely caused by the incorrect country code configured on the AP. The available power range that can be configured may vary based on the selected country code. You can check which country code is currently configured on the AP and then change it back to "CN" to restore the power range to 1-20dbm.