Firewall Backup Size Keeps Increasing

Hello everyone,

a little over a month ago I replaced the machine running my home firewall, and since then I’ve noticed something quite strange that I can’t really explain.

Every week I regularly perform a backup of the configuration. The system is now stable, I’m not making any particular configuration changes, and the only recent activity has been a firmware update.
On top of that, the backups are created without including logs, so I expected the backup size to remain more or less the same over time.

But that’s not what’s happening: week after week, the backup file keeps getting larger.
The increase is not massive, but it’s enough to make me think that something is changing “behind the scenes,” even though everything appears unchanged from my point of view.

What really confuses me is this:
if the configuration is basically identical and logs are excluded, what is causing the backup file to grow?
Is there some internal data, cache, certificates, database, or other dynamic element that I might be overlooking?

I’m curious to understand whether this is normal behavior or if there’s something I should investigate more closely.