I did a frequency usage and noticed 5270, 5550, 5690, 5775, 5820 all have noise floor of exactly -60 but frequencies above and below is -100 or -90+ ?

can't confirm. but we are over thousand km apart.

maybe interference was occur if you want to know which frequency is good for you choose the highest one for example -100 is very good than -90 an so on.

What is noise in wifi? Noise is a RF signal that cannot be decoded as 802.11. NOISE is any signal (interference) that is not WiFi traffic such as cordless phones, microwaves, radar, etc.
This means there is a transmitter using that freq, but is not using one of the 802.11 understood encodings.
NV2 or Nstreme would have been recognized by a Mikrotik device. Others do not understand that signal.
A camera or alarm system may use this, any IOT device, a drone, home automation .... just anything that is sending not 802.11 compliant signals.
( Would 802.11ac recognize all 801.11ax ??? Normally 802.11 is backward compatible.)
Does Snooper (with "Receive errors " allowed) reveal any MAC address?

I just left the frequency usage running for a hour and so far 20 frequencies are reading a noise floor of -60, I am just wondering if this noise floor is from onsite AP's or PtP's or both?
The list of -60 noise floor frequencies varies from 2 to 6 and max of 8 at any given time!

Check with "Snooper" (that other tool besides Freq Usage) , and if used with "Multiple channels" and "Receive errors" enabled under "Settings", it might even show more 'sources' of the signal.

Does Snooper (with "Receive errors " allowed) reveal any MAC address?

Tried scan with "Snooper" but didn't get any extra information!

I also did a scan from a CPE on the same mast pointing in the same direction and it did NOT pickup any noise-floor frequencies with -60 ?

My conclusion is that maybe one of the pigtails on the RouterBOARD R11e 5HacD 802.11ac is NOT seated properly but this will need to be taken down to be checked?

Update - just discovered that

(1) 3 X RF Elements HG3-TP-A60 60°Horns using Mikrotik RMB11G + M11G miniPCIe, at one site have Frequency usage reporting a noise floor of -60 at certain frequencies ,

(2) At another site 1 X RF Elements HG3-TP-A60 60°Horn using Mikrotik RMB11G + M11G miniPCIe is also reporting noise floor of -60 at certain frequencies,

I would like to ask if anyone else with similar board + radio card have the same issue using RF Elements HG3-TP-A60 60°Horn

Update - The -60dBm noise floor is appearing on all RF Elements Antenna's 60° + 30° + SEC-CC-5-17, at this stage I am thinking that the issue maybe a Mikrotik ROS software glitch because the -60dBm is appearing on live production devices and they are working flawlessly since put up in the spring this year,

I did some frequency tests

(1) 20Mhz scan : No -60dBm,

(2) 40Mhz scan: just 1 result -60dBm

(3) 80Mhz scan : 2 results -60dBm,

Must contact Mikrotik Support to comment on this?