Yes.
Read the manufacturer’s instructions for these bulbs – – they almost certainly say that they are intended to always be on power, not to be turned on and off.
If so, is it a better idea to have them “always on” and use a z-wave motion sensor outside to control the lights?
Yes, but getting the motion sensors to work correctly outdoors can be tricky. PIR motion sensors work by detecting very tiny changes in heat moving across the sensor. If placed outdoors, you tend to get a lot of false alarms from Gusts of air or even a cloud passing across the sun.
For this reason, most of the Z wave and zigbee motion sensors say they’re not intended for outdoor use. Aeon Labs Multi sensor is rated for outdoor use, but the manufacturer specifically suggests disabling the motion sensor function and just using it for light and temperature if it is used outdoors.
There are some people who have been successful using zwave motion sensors in a sheltered area covering a fairly small detection zone, so you can always try it. But it can be problematic.
There are two main options. The first is to use Mike Maxwell’s zone management smart app which will take the readings from several motion sensors to create a zone. This can significantly reduce false positive alerts.
Alternatively, people tend to use different technologies outdoors. Geopresence and/or Ibeacons Can work for detecting household members. Trip beams and pressure mats are other alternatives.
And many people have motion-activated outdoor floods which are not connected to their smartthings system in combination with other lights which are Networked, but through indoor smart switches. This is what we do at my house. But different things will work for different people. 