Web UI - 404: Not Found

Been running a Woodworker X50 (v1.3.0) almost a year now. During that time, no major problems aside from the occasional “Aw Snap! Something went wrong” when we had a 1080p webcam connected (now running with a 720p webcam - the recommended Logitech C270). Controller is connected to 1 Gb LAN by wired ethernet.

In the last two weeks we’ve had a new issue crop up:
The controller UI eventually goes unresponsive on the connected touch display. Attempts to connect remotely to the Web UI result in “404: Not found” page being displayed. The controller web server is responding, it’s just not serving up the Web UI anymore. Similarly, attempts to connect over SSH fail - after the key fingerprint response and password is requested and provided - connection closed by server. The controller does respond to ICMP pings

We have to reboot the controller, after which we can connect to the Web UI and/or SSH as expected.

Fortunately, in all cases this occurred during periods when the CNC had been idle for several hours.

It occurred most recently while a remote connection to the Web UI was active (previously established). The video feed from the webcam was still live - even though the UI was unresponsive to input and other remote connections produced the “404: Not found” response from the controller. It appeared the Web UI’s websocket connection was still active, periodically receiving zero-length messages from the remote server.

The only change made recently was replacing the 1080p webcam with the 720p webcam.

Can’t find anyone else describing a similar problem - Any thoughts?