Backup Config file size growing

I’m running 3.10, 3.11 and 3.17 on Intel in an OSPF setting with 25 other routers. The size of my backup config files will grow 100 to 200k per day on average. Anyone have any idea what might be causing this? If I reboot the router, the file size then returns to its normal size (~30k)… then starts growing again. After one day, it will be ~200k, then next ~400k and so on.

thanks in advance!