Hello,
I've installed fresh i-mscp 1.3.0 on lxc container and here is some problem:
After adding some domain to panel and enabling php to it, I get error 500 while trying to open any php file on that domain, in logs I have "connection failed" errors regarding socket for php5-fpm. The only way I can fix it is restarting the container - restarting apache, php5-fpm etc doesn't work in any way. I have still not investigated what exactly is done during container restart which makes this things work.
Also, when I change something like allow_url_fopen directive using panel it also makes it effective after container reboot. Restarting any invidual services would not help.
I was not facing any problems like that in any versions before 1.3.0 so I guess it is something related to this version, or maybe this version and lxc containers.