Samba
nano /etc/samba/smb.conf
NFS
nano /etc/exports
look at your crontab
crontab -e
maybe there are scripts listet which are getting called for your rsync
just two weeks ago I turned my back on turnkey file server
backuped all settings within webmin
I installed a new debian lxc
https://community-scripts.github.io/ProxmoxVE/scripts?id=debian
integrated webmin (use the script inside your lxc ...
I have multiple Proxmox Nodes (since version 7) running with turnkey file servers and never had a problem like yours.
But I dont gernerate a storage for the lxc, I manually mount the folder
example, your turnkey is lxc 100 (file-server)
you open...