I believe I have run into this issue with a client.  They have a pair of MS425s as their network core, connecting to a pair of Nexus switches for their server access block via a port-channel.  The issue seems to repeat every 1 to 3 weeks.  All cabing between the switches has been replaced.   Intermittently, the Nexus switch starts seeing the ports connecting to the MS425s start flapping in 30s cycles, and eventually, the Nexus switch errdisable's them - permanently.  Errdisable recovery will not enable the ports.  Disable/enabling the ports does not fix them.  Unplugging the 10Gbe TwinAx cable from one of the LACP members, and then plugging it back in again fixes it.   I note in the latest MS release notes for 17.2.1 it lists this resolved bug: "All new LAG configurations will block redundant links if the connected device is not configured for LACP. This change fixes an issue where switches would sometimes move LAG ports to an active forwarding state prior to LACP convergence, creating the potential for loops. The change does not apply to existing LAG configurations.".   I also take it to mean that after you apply this firmware, you need to delete and then re-create the LACP group. ... View more

Oh man,.. I've been fighting with LACP since 15.21.1.  Tell me, when your LACP links seem to be working properly, do you randomly have STP take them down?  Also, do you have intermittent traffic issues, some devices seem inaccessible from one device but not another on the same switch, then suddenly the issue resolves itself?   My upgrade today to 16.9 seems to have made LACP worse than 15.21.1 because it used to feel like just Cross Stack LACP was an issue, now LACP between two single switches is also giving me fits.  I've disabled one link in the LACP group for all of our 66 switches for now until I can figure this out.  With the link disabled everything is working perfecty.   James ... View more

Yes, when updating or I think when rebooting the devices to be more specific. But on a daily basis I'm not having any issues, so what you are experiencing is very weird. Have you contacted support? Can you share all settings from the ports on both sides here? Maybe there is something that you are just missing? ... View more

Thanks for the info, we will look into this and try to just upgrade a small network first. Thanks! ... View more