Shoutout to @0scar for posting a photo of the filament sensor, that was super helpful. Also thanks to everyone else who pointed me to the filament sensor and resources around that.

I also tracked down [this review](https://www.printer3d.org/3d-printers/alfawise/alfawise-u20-large-format-3d-printer-review.html) which had great information around my printer's filament sensor as well. It turns out that the hole that goes to the sensor is way too big and there's a lot of play with the filament. As I jiggled the filament up & down I could hear the sensor clicking on & off, clearly indicating that if the angle of entry of the filament was too low, the sensor would not be depressed and this would continue to be a problem.



So for my next print, I did what that reviewer suggested and simply unscrewed the sensor & taped it so it would not stop my print. My print was unsuccessful for other reasons (under-extrusion/failed to adhere to the build plate 😫), but at least I think I've figured out what's going on with my filament sensor. Thanks again everyone!