I've been running Octoprint successfully on a RPi 3B+ and a Logitech C270 camera and a Prusa MK3s.
I've now attached a Logitech C930e as a second camera. I followed the instructions on https://www.makersmashup.com/post/outside-the-box-multiple-webcam-setup-with-octoprint to set up the second camera.
Everything works fine until I start printing. After printing one layer, Octoprint crashes hard. The print just stops dead in its tracks, and I have to reset the printer and reboot the RPi to recover. The log files don't show any errors. I can still ssh into my RPi, though.
One other thing I find odd is that I set the framerate to "-f 1" in octopi-cam2.txt:
camera_usb_options="-r 1280x720 -f 1 -d /dev/video1"
And yet, when I stream video directly from the camera via VLC, the frame rate is definitely faster than one per second. Is -f1 too low of a value?