@Brons2 we've not had word of a fix yet, and we have chased.  We're sitting tight until we've been advised that root cause is known, and fix written.  Too much disruption last time to take any risks. ... View more

No fix as yet. Workaround in place, uplinks on stack master only, and stable since the change was made, and I've been making changes up and downstream without issues for so far - the apparent trigger for MAC table problems. Agreed, lots of pain that can be done without. Sitting tight sounds like a wise plan. ... View more

PhilipDAth thanks for the info.  Curiously, in our case, I could see ARP requests and replies to the default router from the stack at regular intervals yet the entry never appeared in the MAC table.  Our routing problem seemed obvious, we had a default route entry in our routing table although no entry in the MAC table to enable forwarding.  We also had other intermittent forwarding issues with client/server relationships across the stack - one almost completely killing public DNS lookups for a subnet.   We resisted CTRL-ALT-DEL to help find root cause and worked around each issue as it arose.  After a few calls to support and plenty of troubleshooting thankfully the issue revealed itself.  Lots of pain although we got there in the end. ... View more

Just to qualify my last comment. Our experience suggests that there is a known issue with MAC address tables across the stack. However, not all topologies will necessary be sensitive to this issue and we haven't seen root cause from support in black and white yet.  You may be experiencing a different issue.  Go back to support. ... View more

Had major problems with a four switch MS350 stack after upgrading to 11.22, though only after making downstream and/or upstream changes.  Played intermittment hell with our two (active/passive) uplinks for routed traffic, though curiously not with L2 traffic.  There appears to be a known issue with MAC tables being correctly propogated across the stack, though I have no idea how general the issue is.  Our issue worked around by moving the uplinks to the master.  Fix in the works.  Make sure the uplink(s) are on the master.  Log a case if you have any doubts. ... View more