Problem on AX6S after 15 days of operation, solved by reboot without explanation

[po220]

I had a problem with an AX6S with openwrt which was resolved by rebooting without understanding the origin of the problem. I need held for understanding origins.

Startup of the router on May 19 with several interfaces and SSIDs including 1 main network accessible either by Ethernet or by wifi. A configuration very similar to this one

First config, review possible (on AX6S)?

I just did my first openwrt setup (on an AX6S). It corresponds to an old network that I had to manage. This config will never work in real life but I will have very similar configurations in principle. I have read a lot of things and tried to do it right but could you please criticize the config ? Everything seems to be working fine but there may be a big security issue or bad practice. Thank you very much dhcp config dnsmasq option domainneeded '1' option boguspriv '1' option filterwin…

Everything worked perfectly from May 19 to 31 and on June 1st :
All interfaces OK
All Wifi SSID OK
internet browsing and most activity OK

but

1. a local nas could no longer access a remote nas via Rsync, connexion error (while the manual connection in SSH worked)
2. Local Robocopy operations (SMB) worked perfectly if wired connexion and were unstable and extremely slow over Wifi (with several machines and while the wifi worked wonderfully for all other operations)

What happened on the first of june?

Thanks in advance.