Alright... So I've now verified that having 802.11k, 802.11v and 802.11w enabled does not influence the situation. Having them enabled, I've confirmed that a combination of wireless.default_radio0.encryption='sae-mixed' + wireless.default_radio0.ieee80211r='1' causes problems. Changing any of them makes everything work.
So the workarounds are:
- If you have a single AP and don't need Wi-Fi steering/roaming — just disable 802.11r and you can keep
sae-mixed. - If you do need Wi-Fi steering, you'll have to choose either WPA2 or WPA3. If you don't have ancient devices, go for later. Otherwise, stick with the former for the time being.
P.S. Interesting observation: when I had an iPad connected with sae-mixed + 802.11r disabled, and then enabled 802.11r (causing the AP Wi-Fi interface reload), the iPad stayed connected (well, I guess re-connected almost instantly) and toggling its Wi-Fi switch off and on again keeps it connected. But if I disconnect for a while and its internal state resets/times out, then it won't be able to connect back at all, reporting the infamous Unable to join the network "***". This seemingly obvious nuance makes troubleshooting a bit more troubling. Beware.