I am experiencing this very same issue. I have read through this thread and tried some of the suggestions such as disabling band steering and ensuring channel width is set to 20.
I have also tried:
- Moving DHCP from the Meraki to the LAN
- Establishing a static IP through DHCP reservation
- Isolating the SSID to a single AP at arms length away from the Pi
The interesting part is that I recently replaced ~30 Aruba APs with the Meraki MR42s. Previously with the Aruba APs in place, no problem was visible and the Pi's had weeks of uptime. After replacing with the MR42, the best uptime i experience is 3 hours.
I would like to experiment with different firmware versions but it appears i can only push a new firmware across an entire network rather than the one i am using for testing. Is this correct or is there a way to flash firmware on a single device?