If you are experiencing the dhcp issue (that ends with a lease failure), please try the following solution that was shared by another member of the forum:
The reason why “lease fail” is shown, is because dhcpc conflicts with udhcpc. Fixing this is simple; Add “denyinterfaces wwan0” to bottom of /etc/dhcpcd.conf. Then restart dhcpc “sudo systemctl restart dhcpcd”, followed by restarting qmi_reconnect “sudo systemctl restart qmi_reconnect” (or reboot).