It looks like we are also having this issue. It appears that as of early in July, all was working well, and then sometime between July 6th, as the last time I had to manually manage an item, to today when a few issues were brought to my attention, something happened.
I saw a message when I was running updates today on a few iOS devices, that I couldn't get accurate info in the Meraki Device listing for the devices. (Location was wrong/missing, even though the App was giving green checks across the board and the Web console said it was updated within minutes) and it would not send any commands to the iOS devices.
I attempted a test by removing one device as a test, clearing the MDM profile, and re-adding it as if a brand new iOS Device. During this process, I found a message that Meraki was "experiencing issues with the Push Certificate with Apple" and asked for it to be updated. (only 4 months in since we updated all the certificates, so it wasn't expired) So I re-downloaded the tokens/certs from Apple and uploaded to Meraki, and continued with re-provisioning of test iOS device.
Once completed, as usual, it added the profile, but it appears that the SM App is never pushed to the iOS device automatically, as it always has and is instructed to do. Finding this Odd, and after a 2nd test where the exact same result happened of the SM app never being pushed out, I attempted to manually download the SM app from the App Store associated with the main Apple ID account.
Once downloaded it asked to be associated with the Meraki ID, so once provisioned in this manner, it appeared to be connected with green check marks down the line, but Meraki showed the device as "iOS Device" with iOS 11 (and not either the iOS 11.2.5 or the iOS 11.4 as they did previously)
From what it appears, from one of the latter messages (at the time of my posting) it appears Meraki's message just indicates that they are "working on it" and that we should just sit tight, am I correct?
Thank you again for this thread, as it is reassuring that I am not the only one experiencing this issue. Fingers crossed for a speedy resolve.