Report "My garage door opens properly but upon closing, it advances a couple of inches and retracts as though something obstructed the sensors path and the led over the learn button begins a 2 flash sequence. If I disengage the door, the LED over the learn button stops flashing immediately and the all is OK the opener. I could open and close it as many times (with the door disengaged). It's been installed as is for the past 4 years with no changes!"