Private (random) MAC, or not, when my iPhone is connected to my local 'office' wifi it keeps replying on my pings until it lockes down.
And to my suprise, my phone is locked right now, and it sill replies to pings (I really thought it would de activate the wifi when it sleeps *** ....)
When you connect for the first time, with private (random) MAC activated, that MAC address will get used every time you use that SSID.
If the MAC was really randomized every time the wifi reconnects to a known network, users wouldn't be able to use a network with a captive portal ;)
As soon as I activate my iPhone again, it reconnects to my office Wifi immediately.
Because I "told" it to do so.
Exception (I'm not sure - the Apple doc will tell) for those who activated the "spare battery mode" (signalled with a yellow battery indicator ?) you have to tap on the wifi SSID to make it to reconnect.
I confirm that I had never had issues using whatever Wifi network using whatever iPhone using whatever iOS version.
And if there were isues, billions would see the same thing, and Apple would have applied an urgent iOS update.
So, @davidki, tell us about your setup, and we'll tell you what's wrong with it ;)
An example of an issue would be :
Bad Wifi (radio) signal, mixed with other SSIDs that emits on the same frequency, etc.
To many AP's in the neighbourhood.
To many devices on one AP (noop, the basic ones can't handle many devices at the same time).
And also : DHCP issues.
edit *** : and when I think about it : I was mistaken.
When you switch from 3G/4G/5G operator data carrier to a wifi 'Internet' source using some Wifi network around you, your phone is reachable by the Internet-over-wifi connection, not your operator's carrier (and Internet connection).
When the phone stops the wifi, it wouldn't be able to receive mail pushes, VOIP calls etc in real time. So, no, the Wifi connection (the radio) shouldn't stop, even when telephone is locked. It probably goes is some low power consumption mode.