hAP AC3 5GHz settings ignored by Quick Set in Home AP Dual mode

Brand new hAP AC3 router batch.
Tried with 6.47.8 as well as 6.48.2..

Quick Set does not save 5GHz radio parameters when “Home AP Dual” mode is selected. When I try to change network name, frequency or band, they just revert to previous settings.
I am able to manually change these parameters directly, via winbox or webfig.. Just not through Quick Set.

2GHz settings work fine.


Any suggestions would be appreciated!