Fluctuating signal strength

I’ve tried inSSIDer on 2 Windows laptops (drivers up to date) with different Intel WNIC (ac and ax) and on both the signal strength is fluctuating all the time by 7-9dBM. Its especially noticeable in 2.4Ghz as below.
Distance/attenuation doesn’t make a difference.

If I associate to an SSID on the AP it becomes a stable straight line.

Any ideas why I see this?

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By any chance is this on Cisco AP’s? Not surprising, they are a train wreck…

No its not.
I’m now thinking its more do do with Windows and/or the Intel WNIC/drivers for passive scanning.
I put another AP in monitor mode and did a packet capture on it. It shows the RSS in the captured packets to be consistent within 1-2dBm.
Oh well, onwards and forwards…