Hi @Skinner I have seen Chromebook deployments, for example in many K12 environments, and on rare occasions I have seen some oddities with connection drops like this. Please do open a case with Meraki Support for investigation. Your plan to try dropping back to GA firmware 26.8.1 is fine if you want to do that first, that will be a good data point if the issue persists across both MR26/27.
In some cases, I've had deployments that had all other devices working perfectly (windows laptops and iPads for example) but ended up with specific model Chromebooks and/or with lower-end wifi adapters that exhibited such issues which somehow went away with the next CRos update. Sounds like you've been through one OS update already. And I'm not pointing fingers at CRos, just stating what I've seen on a few occasions. Do you have any other makes/models of Chromebooks, even a personal one, you can take on site and try to reproduce with that one also?
The best next step (perhaps after firmware) would be to get that case open, and capture this issue while it's actively happening, while collecting a monitor-mode packet capture. Do you have a Macbook? If so it'll be a simpler process. You won't be able to just run Wireshark on the wireless interface of a laptop for example, you'll need to run a "monitor mode" pcap and get that to Support so the Eng team can decode the exact sequence of events/frames leading up to the drop. If it's a random thing, and can be tough to reproduce, you can also set up a "rolling" packet capture, and perhaps give yourself a 5 to 10-minute window to go stop the capture when the issue occurs. Support can assist with the setup.
