Following the FragAttacks announcement I have upgraded my R550 AP to 188.8.131.52.243 only to find subtle connection stability issues between the AP and a Linux ThinkPad T480s with a Intel 8265 wireless chipset. The symptom is that any tcp/udp/icmp package transmission just stops after 1-2 hours of usage. After reverting to 184.108.40.206.233 everything is rock solid once again with connection not breaking at all for days at a time. I have tried WPA2-only and WPA3-only modes both with both firmwares and the results are the same (233 is stable, 243 causes dropouts).
Any ideas where to look next or what might be causing this?