If those devices are outside, and at a fair distance from the hub, you more than likely are experiencing range and/or interference issues with WiFi.
Rejoining those devices may help, but you’re going to want to add a repeater, like a zigbee wall plug (Ikea, GE, and others are talked about in the Community).
Did you change your WiFi router lately? Did you move it or the ST hub around lately? As odd as it sounds, did a close by neighbor add a wifi router?
The article the other member posted shouldn’t concern you, but I would look into what changed that you can control, or add a repeater to your zigbee mesh.
Oh, BTW, you should probably remove all your personal contact information you posted above, as well as stripping it out of any of your email replies that add that info from your signature block when you post replies.