The most likely cause for this is that something is triggering a graceful restart of Apache. Most likely this could be your system logging system doing a restart of Apache because of the need to rotate log files.
Apache actually has its own way of managing and rotating log files so that there is no need to do a restart of Apache, but Linux systems totally ignore that and do it their own way, which in the default configuration with mod_wsgi can result in this error, since you get stale socket information in Apache child worker process since the socket for the daemon process group gets changed on each restart, yet Apache child worker processes when graceful restart is used can hang around longer if keep alive connections are used for clients.
Seems it is missing from the main docs and only mention in change notes, but you can try setting:
This will cause it to use the same socket name for daemon process groups across restarts.
Make that change and see if things improve.
Also look at the Apache logs and see if you can confirm if anything is trigger an Apache restart. You may need to have the Apache log level set to info rather than err or warn to see information about restarts.