after update to 25.1.5 between to OPNSense firewalls over a VPN Tunnel we are seeing significant traffic issues. We are seeing ping response times up over 100-200 and traffic at a crawl. We continue to make minor changes and it fixes it self for about a day, but then the problems return. Even moved them from an ipsec tunnel to wireguard and it didn't help. We are at a loss at this point.
Which type of VPN? Is the MTU the same everywhere? Same behaviour in IPv6 as well? What do the packet traces show?