Currently on the latest version of armbian I am experiencing high background internet data usage. I am limited to a 50MB plan which works fine with other devices, but seems to not be enough for more than 10 days on this distro. I have tried disabling all periodic checks for updates, but I am still seeing high data usage. Any ideas on where these might be coming from? I can provide a wireshark PCAP if needed.

Unattended upgrades will be the first thing to disable since even without actual upgrades package lists will eat enough traffic (use "sudo apt remove unattended-upgrades" to do that).