Less free space after each reboot

Hi, I'm using TP-link archer C2 v3 and latest stable openwrt build (22.03.2). And I have strange "bug". I noticed, that after each reboot there are less and less free space on router. It "eats" several kilobytes after each reboot. What's wrong with it?

Have you configured logs or a non-default package?

I customized firmware via firmware selector. I deleted dnsmasq and odhcpd-ipv6only. Added dnsmasq-full and luci. I did that, because I need dnsmasq-full and https-dns-proxy. I can't install them both if I use standard 22.03.2 image, because of 8 mb memory space (I dunno, maybe in that case I can't really delete dnsmasq, right?).
Didn't touch logs.

Maybe download entire storage before and after reboot via winscp and then compare sizes?

After reboot:

Before reboot: