Variable TX/RX rate

When TX/RX rate of a wireless interface (i.e. 260Mbps-80MHz/2S/SGI) is changing continously, is it symptom of an unstable radio link ?
Noisy, crowded channel etc ??
Thanks

If an oven doesn’t consume the same amount of electricity when it reaches the desired temperature, is it broken?

The comparison has the same precision as the question…

A radio link , expecially in wi-fi band urban environment is normally subjected to interference expecially with high SNR and weaker signals.
I have few ac radio links with roubust signal (less than -50dBm), that are rock-solid stuck H24 at 866Mbps-80MHz/2S/SGI despite the traffic passing by
Others with lower signals (-60-70 dBm) that are changing over and over , I just want to know (as I don’t) if this is an expected behavior due to dynamics of radio channel itself.
Is perhaps that index adaptively changing , based on amount of data traffic passing trough ? (It doesn’t explain the 866Mbps data-idle speed before…).

Thanks.

P.S. I’m talking about PtP link.