I saw something similar @Griff. The carve finished and I didn’t notice until it was almost done.
Just did a test (not on a real carve and not when it was “frozen”)…
Clicked View --> Reload
CNCjs looked like it was disconnected, but serial communication was still going.
Opened connection again, and it was still going, running the whole time in the background.
Looks like the same as this?