I have reported issues with the RF spectrum numerous times, through support cases and even guys that come to our premises to hold a session.
This has been two years already and I have never seen the RF spectrum visual work properly.
I now have a clear example with a very busy 2.4 GHz spectrum that while it says channel 1 is very busy, the visual still centers the busy-ness around channel 5 for some reason.
And even worse for the 5 GHz, the graphic has never showed the UNII-2 and UNII-2E bands.
I once had an answer from a support agent stating that DFS channels are almost never used... We use them all the time!
These screenshots are from an MR46 in trial for a survey at software 26.7 now.