In some logs we could see following error :
ERROR | caf_writePipe: failed to write sig to pipe: : (232) The pipe is being closed.
ERROR | caf_writePipe: Some error occured
This error could occur at shutdown of the machine.
If caf has problem to stop during the shutdown, it may send messages using pipe to plugins which have already stopped.
This error could be ignored as it does not indicate a problem in working of product.