I noticed a weird issue that I cannot determine the actual reason after upgrading to 6.48.1. All I can confirm is the issue happens only on 6.48.1 but not 6.48.
The issue is related to VLAN. I have several VLAN configured on my network, they are mostly to isolate different kind of network devices. After upgrading to 6.48.1, one of the VLAN (VLAN ID 19) stops getting access to the router, but all other VLANs and untagged are working just fine.
On my network, I have assigned an IP and subnet for each VLAN. Untagged has a similar setup. After upgrading, each VLAN can ping their corresponding gateway IP without problem, and cross VLAN routing works. But just VLAN 19 it cannot reach router. From winbox I can see devices on VLAN 19 sent DHCP request and router offered address, but no packet is received at devices. From device all I see is a big 0 on received packets.
I tried to lift all firewall rules, shuffle ways devices are connected (remove intermediate switches), nothing helped. Once I downgrade to 6.48, the issue is gone. I tried to upgrade to 6.48.1 again, issue is back. Restore configuration did not help.
There's nothing seemingly related to the issue from change log. Or am I missing something?