I am having a semi-similar issue which may indicate that I need to do the firmware upgrade to 25.10 as well.
Started at a new company where we are having an MTU issue where I can't have a packet size greater than 1462 over wireless. The easiest way to replicate this is using ping. If I use windows with a "ping 8.8.8.8 -l 1420 -f" (as windows take the 42 bytes for the ICMP packet) and I get a response, but 1421 and I don't.
After various tests I have isolated the issue to the wireless network as I don't get this issue over the Switch -> Router -> Internet and don't have this issue on other wireless networks so have ruled out my laptop.
Since the firmware was upgraded over 2 weeks ago I can't roll back but there has been various complaints of certain sites being unavailable and VPN connections not working "for the last month or so" which to me sounds rather coincidental.
Planning to take a non-Meraki AP onsite tomorrow and have that option to test, plus upgrade to 25.10 when I have a failback position with a secondary AP as the site principally uses wireless for all devices and there is only two APs.