Hi Paul,
We certainly understand the frustration.
Unfortunately, the behaviour explained above is exclusive to X440-24t switches.
Check this article out:
https://gtacknowledge.extremenetworks.com/articles/Q_A/Is-it-normal-for
For the other switches, the behavior is different and the fans are always running and shows 11000 RPM.
https://gtacknowledge.extremenetworks.com/articles/Q_A/On-a-X440-the-fan-speed-is-always-listed-as-1...
It is good that the switches are not rebooting and it should not make a difference if more traffic is pumped in. Because, the fans would rotate when the temperature approaches 48 C and it will cool the sensors.
However, it would be a best practice to position these switches at a place where the temperature do not go so high , especially it would be good not to position these devices on top of other switches..
Hope this helps. Let me know if you need any further clarification.