Hello @Robert_Fielder,
I have enabled diagnostics on your account so our technical staff can get some more insight into what’s going on here. The next time your Core is active a diagnostics report will automatically be generated and uploaded directly to our servers
Once that’s been received, I’ll be sure to update this thread and pass the diagnostics over to the team for further analysis.
I usually like to mention that we’ve tracked a number of issues to in the past to managed switches(examples: here, here, and here).
The simplest way to confirm whether the switch (or its settings) are contributing to these symptoms would be to temporarily test with the switch removed from your network. Whether things improve or not, the results of that test would be a great data point.
I would also recommend enabling flow control on the switch, as we have seen that settings resolve a number of issues for other users in the past
-John