I have the same issue than you a 23 switches MS150. Mix of MP and FP. All are stacked (2/3/4 switches) I have 2 MX250 on top and 1 stack of 3 switches have the role of CORE so each MX have only 1 link connected. (Meraki recommandation).    I observe the same behaviour in the logs : SFP detached / Inserted. But not all sfp ports.  I also have a lot of "BPDU Sender Conflict" in the logs on every single upling of each stack. It's a nightmare.  Apparently this is caused by quick Stack flapping no visible on our frontend. Only possible to monitor on Support Backend... He said me the issue is affecting some clients and for some of them the 18.1.1 is solving the issue and for some no like you and me. He will ask the product team to check that.  For the story, this issue happened the first day of the opening of my new office of 400 people.... I run that network in test since 2 months without any issues...  ... View more

Are you running any stacks?  I opened a case with Meraki this morning, and they confirmed that we were hitting a bug in 18.1.1 where the DHCP offer was not being forwarded to any other switches in the stack.  In our case, if the APs were connected to the switch or switches that contained the uplinks for the stack the traffic would pass normally.  If the AP was on a stack member that did not have an uplink, and was only using the stacking cables to connect to other switches, then the switch would NOT pass the DHCP offer message to these other switches.  Apparently, the bug was shown to be fixed in 17.2.1, but the support engineer I was working with thinks it was never added to 18.1.1 and is thus a regression for that bug.  We are rolling back code to 17.2.2 as we are hitting way to many issues with 18.1.1 code.  We were told to use it by Meraki support to fix another stacking issue we saw, so we are now having to abandon stacks for the time being until they get all this worked out for the MS150 line. ... View more

Thank you sir, will give those a try   ... View more

Glad to help!!  On firmware version 15.42 our SAP traffic works properly, but we found another application that was incorrectly categorized as bittorrent.  Of course, you cant do the AnyConnect VPN stuff on 15.42, so you are at the mercy of Meraki support and the next version of code they release.   ... View more