DSA with tagged and untagged same port, wireless bridged to unmanaged interface


I'm having random loss of local lan communication where it seem that there is no more data moving from the wireless interface to the device integrated switch (while devices connected to the integrated switch keep communicating fine)

I got 3 Linksys E8450 (UBI) running master (OpenWrt SNAPSHOT r21108-a31b598590 / LuCI Master git-22.297.83017-94dd7fd) acting as dump APs with another device acting a router/dhcp/dns/ecc

All of the receive 3 VLan on their respective Wan port, they are:

* MNGT  = 3 -> tagged
* LAN   = 5 -> untagged/PVID
* GUEST = 3 -> tagged

LAN interface is unmanaged
MNGT is in dhcp client
GUEST is not local and only pass (tagged) through the switch

My problem is that after some hours all device attached to a Wireless AP stop communicating with the LAN, WiFi is still up and connected but nothing on the LAN is reachable
MNGT seem still working fine at the same time

Here there are screenshot of configuration:

All APs are attache to a good quality managed switch
Also as I anticipated before on port lan1 and lan2 there are attached devices streaming continuous data both to each other and to other devices upstream of port wan and there is NOT any stoppage on the communication on the integrated switch itself

Am I doing something wrong?
There is some special configuration for a setup like this one?
Or there is any know bug on DSA for this types of configurations?

Thank you,