@alifThe issue in this case is not that STP is enabled (obviously, it is
for this issue to occur). The issue is that STP was enabled (no config
change) in 6.4.8, and did not cause this issue. So something about the
6.4.9 release changed STP functiona...
This just took down our entire network. I can't find any mention of
spanning tree in the release notes for 6.4.9, and a technical tip in
2020 claims that FortiGates don't participate in STP, but... apparently
they do now? You can switch STP off on th...