This was a strange one to debug: I upgraded the LED bulbs in my garage door openers from 60W to 100W (equivalents). My wife’s garage door uses a track-mounted motor head with a lightbulb on each side. She began reporting that she couldn’t close the garage door after she pulled out. After some investigation using multiple transmitters we confirmed that it would reliably open from up to 100 feet away, but it would only close using the remote transmitters if they were within about 15 feet of the receiver, which is in the motor head … next to the lightbulbs … which are turned on by default when someone is in the garage or crosses the threshold, but usually off when approaching the garage from the outside with the door closed.
Sure enough: some (but not all) LEDs emit RF energy at the same frequency as garage door openers!
So the newer LED bulbs I installed were unintentionally serving as garage door opener jammers!