I’ve checked internally and our Photon test fleet runs reliably for weeks on end - it is always running the latest DeviceOS.
I would like to assist you in debugging this issue - could you please create a ticket on support.particle.io and provide me with example devices and the specific AP model you are seeing this issue on.
This thread will now be closed and we encourage anyone experiencing similar issues to either start a new thread for up to date information regarding the latest DeviceOS and Wifi or to create a support ticket at support.particle.io so that we can help you gather logs and figure out where the block is.
If you want to grab logs yourself, please see https://github.com/rickkas7/photon-clouddebug for instructions.
Engineering have looked into the issue and the consensus is that it is likely an incompatibility between the Broadcom WICED WiFi driver and the particular AP, or something in the user application that is creating a problem.