aaPanel_Kern
It does not solved for me. The lines you mentioned is already there.
I think the problem is, when the nginx service try to start at boot it cant. I think it conflict with some other process, or starts before the bt panel.
I have a workaround:
Delay the nginx.service 20 sec. To to that, add this line to the /etc/init.d/nginx file: (bellow the "start" line)
sleep 20
It works for me. Now its starts normaly. I cant find the reason why this is happening. It depends on other services etc...
I hope this is usefull for someone, cause I strugled 3-4 hours until I found this meethod.