[Lurker]

Move one of the lights and I think you'll find the problem disappears.

L

[HAL9000]

X10 protocol can use your electrical wiring to control both lights in tandem with a single sensor.

[OldFriend]

Point these lights too close to the ground and you'll have animals tripping the lights all night long. Deer, racoons, cats, dogs, you name it.

If you have a security concern, why not just leave the outdoor lights on at night.

The new energy saver bulbs cost practically nothing to burn.

[spunkets]

"I am sure that the surge created when one goes on mimics the "off-on" of the wall switch, telling the sensors that I want the lights to stay on."

Nah, no such thing.

It doesn't matter if they both go off. They're being trigger by the same stimulus. They stay on because the timer is set that way, or there is no timer and it's a toggle switch. You need to set the timers, or obtain timmers. Could be you need to buy the whole trigger timer combo, but maybe an alarm tech can modify what you have.

[HangThemHigh]

My motion detector lights have settings for sensitivity and length of time to stay on. Changing those may help if your lights have those controls.

[fireforeffect]

The sensors are cheap thermal sensors. If one light points towards the other's sensor, they trip each other. Fixes: A. Make sure lights do not point at sensor and that there are no reflective surfaces out there., B. Turn down the sensitivity of the sensors.

I have these lights around my house, with more than one on each circuit. When they come on (Cows, bats, etc.) in the summer, sometimes the bugs keep them on.

Also wind can wag the trees and bushes and set off the sensors if the sensitivity is set too high.

The way to test the sensors is at night, have some one else turn off the lights, walk to the tree line, they turn on the lights/sensor, and you move. Keep turning down the sensitivity until they do not activate when you move, then back off a little.