My UAP AC Pro have started switching over to 80 MHz wide channels rather than staying with the manually configured width. I can’t seem to find a setting to prevent this from happening.
I don’t have the Auto-Optimize Network setting enabled.
In 40MHz, you will not get as many channels as 20MHz, but you can still get 12 non-overlapping channels if you use it with a frequency of 5MHz. You can use this channel bandwidth with 2.4GHz and 5GHz. If you need a higher data transfer rate, you should go for 80MHz.