I have a Protectli FW4C firewall PC which was successfully running OPNsense until two days ago. I attempted to set it up to handle VLANs with a separate router without adjusting the DHCP ranges first, and the ranges reverted to assigning to 'any' interface. Ever since then, DNSMasq will not tag DHCP leases with the interface concerned, and I cannot get traffic that should be tagged as such to pass since it is not tagged. Because of this, I also lose connectivity to the firewall if I shuffle the connections to the ports. Note that when I do initial interface assignments, the ranges are tagged appropriately.
I have tried re-flashing OPNsense and downgrading it to 25.7, and the issue persisted. I will try downgrading to 24.7, as Protectli states that version to be fully tested. I know this is likely a hardware issue, but I'd like to rule out a cause by any aspect of the software I am not familiar with.
I suspect this is happening due to a configuration file on a partition that is not deleted by the OS installation process, but I have to figure out which one that is exactly.