I had that issue with MR52's on 25.X train, and once 26.3 came out it seems to have resolved it. They are on 26.6 now and I have not seen any issue for a while now.
I would open a case with support as they can take a look at the logs on the AP (stuff we can't see) so they can get a better idea of root cause.
I know one of the things I had to do on the switch side (2960X) was manually configure max power on the ports they AP's were connected to since negotiations were having issues and sometimes they would show that they were operating in low power mode.
We have been experiencing a similar issue with firmware versions above 25 with MR42, MR53, and MR55s. Our wireless networks are segmented by site so we rolled back two sites to firmware 25.13 that don't have MR55s (which require firmware 26+) and have seen the connection drops stop and overall connectivity stabilize. Our networks on firmware 26.6 with MR55s and/or MR42s/MR53s continue to have dropped connections. We have a case open with Meraki support as well and have been trying to capture the air when the drops happen per the request but have not been able to because of the intermittent nature of the drops. Havee you found a resolution?
We had a similar issue. SSIDs configured to use the Meraki DHCP would disconnect clients. Our temporary fix was to reboot the access point, MR55, but the issue persisted after the AP had been online for a few days. Clients disconnecting only happened on APs that had more than 5 SSIDs broadcasting. Once we disabled a few SSIDs, client disassociations stopped completely.
We swapped all of the APs it with the same model but the issue started again 2 months later. It seems as if the radios failed and caused them to reboot. Aerials were Meraki narrow patch antennas.
We then changed to MR46E APs and have been operating for months without issues.
As a precaution we had the site analysed for wireless interference with all of the APs turned off just in case something was overloading the radios of the APs. That came back all clear. We even ran the arena LED lighting at full power and they had no interference.
So, we are hoping that the chamber in AP model works fine.