i set up my Urbackup (server runs on a RasPi 4, 8 gig using Dietpi) and have it all configured for all my home computers to do full and incremental file backups. i have notice that the daily incremental backup is about the same size each time (see SS below) and is around the same size as the initial incremental backup.
this computer in question is a computer that does not have active users and runs my security system. the videos are on a separate drive that is excluded from being backed up so i know its not that.
i will note it is like this for all of my computers.
What folders are you backing up? If it includes the user profile it’s normal, it will be various caches etc that change continually so keep getting backed up again.