Error assertion failed on syslog-ng

Hi team , 

it is a pleasure to write to you, i need to discuss on syslog-ng issue .
We have many client syslog-ng service , and we got this error : 

 ERROR:/syslog-ng/pe-builder-image/syslog-ng-pe-project-7-0/syslog-ng-core/lib/logpipe.h:339:log_pipe_queue: assertion failed: ((s->flags & PIF_INITIALIZED) != 0)

And after that, syslog-ng failed and systemd restart it . 

Do ypu have any suggession , we use syslog-ng version 7.0.12