You can use "hw-info" to see all possible bands, channel widths, and frequency ranges of device:
:put [interface wireless info hw-info wlan1]
We've just upgraded from 6.11 to 6.3x.x and this change is bad.
Listing "allowed channels" doesn't list all the possible channels. It lists what the allowed channels are for the current configuration.
ex - If you are using (what used to be called) 20/40Mhz-ht-above, the list does not include 5825 mhz, as that's the extension channel for ht-above.
The list is like: ...5805/20/a,5810/20/a,5815/20/a,5820/20/a,5825/20/a ...which only pertains to the current configuration.