This is not a bug, it tells you that you must install DHCP package now, read carefully the change list:
*) upgrade - made security package depend on DHCP package
And which mobile operators?We're in 2019 and mobile operators sell 50GB/month for 5€, who needs hotspots anymore?
/interface wireless set wlan1 wps-mode=push-button
add action=reject chain=input reject-with=icmp-admin-prohibited
/ip firewall filter add chain=forward action=fasttrack-connection connection-state=established,related /ip firewall filter add chain=forward action=accept connection-state=established,related
Ideal situation. Why you even use 2.4GHz? Stay with 5GHz only and problem solved.forgot to mention that this is one room condition - both phones, laptop and router are in one room max 3m away.