Yes.Are you using 40mhz extensión channel?
Agree, I have similar problem. If a POE powered device is connected, the 750UP completly hangs. I had to downgrade to ROS 6.29.1.Big WARRNING DO NOT upgrade 750UP I have problem on network after couple hours devices just crash some reset by watchdog some not.
I kill my network with this upgrade.
+1OpenVPN server doesn't work. TLS failed appears in the log. Downgrade to 6.10