LuCI: LXC containers are not listed after installation
The issue is that there are no containers listed in LuCI if there are any already or if they are created after that till the reboot is performed.
This happens only if you install LXC not when you remove and install it back on running router. Boot of device has to be without LXC installed.
The cause is missing LXC in ubus. Any direct operation such as creation of container are successful but anything modifying existing containers uses ubus. LXC ubus support is provided by package rpcd-mod-lxc. This package clearly is not forcing rpcd reload.