Odd PPSK without RADIUS problem

I am using OC200 + EAP 610v2 with PPSK without RADIUS authentication. It mostly runs flawlessly.

However, despite that it was working without problems for weeks, tonight my ten-year-old Brother printer suddenly disconnected. After I reset the printer's network setting, and reconnected it to the SSID, I was not able to get a valid IP. I set up a static IP with the correct mask and gateway. In the AP I can see the printer connected with this IP, but I couldn't ping it or make any TCP connection. After re-connecting to the WIFI for a few more times, the printer could no longer be connected to the SSID anymore. So in the AP, I created another SSID with WPA-Personal authentication. This time the printer immediately connected and started to function.

I had a very similar episode with a Ring camera a few days ago. It was working fine with PPSK without RADIUS SSID. Suddenly it disconnected. Then for the life of me, I couldn't get it to reconnect to that SSID. So I also had to create a new SSID with WPA-personal, with which it immediately worked. The difference here is that when I tried to switched it back to PPSK without RADIUS, the camera stayed fine.

I wonder if anyone has seen a problem like this and what would be a possible solution.

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