I have this exact problem and (mostly) fixed it by swapping the sensor and transmitter. I just cut the wires and spliced with electrical tape. Now the problem still happens but only sometimes in the fall and spring when the sun's angle is just right. This is with a west facing garage about 41°N latitude USA.
But yeah, why this isn't laser based, or using a light frequency that is less affected by sunlight? Probably cost, or ignorance.
But yeah, why this isn't laser based, or using a light frequency that is less affected by sunlight? Probably cost, or ignorance.