My garage door was reversing as soon as I hit button to close it. I went through all the troubleshooting steps I could fine online: I adjusted the the travel distance and the weights, I check the electronic eye for functionality and alignment, I looked for broken gears and sprockets. At that point, everything said that I needed to replace the rpm sensor, which looks like a heavy duty version of the sensors that you’d find in old roller ball mice.
I ran a piece of paper towel back and forth through the slot on the sensor board and that fixed the issue. I thought it deserved to be written down somewhere, but I’ll put it in some forum if I get the chance.