Posting the reply from Support as I think it may be helpful to some:
Thanks for reaching out to SmartThings with all these great details! I’m sorry to hear that some of your GE Z-Wave switches and dimmers are giving you a hard time connecting, but I’m happy to help out.
Based on the data from your Z-Wave network repair, it sounds like all of the current devices in your network are routing signals back to the Hub using the best route possible. To explain the “skipped” device IDs that you noticed: sometimes when a device pairs or is successfully excluded, it will get assigned a device ID from the Hub. When the device no longer is on the SmartThings network, the device ID is gone and does not get recycled unless you start your Z-Wave device table over again. Likely there was either a partial connection that did not go through or a previous device was assigned that ID. This is pretty common in large Z-Wave networks and likely should not cause any problems or is something to worry about.
Looking at this data, there are likely two things going on here: the switches are not receiving exclusion commands properly, and there may be interference from other nearby switches. With two devices near each other, it may be the first one that connected is now drowning out the signal from the Hub for the other one.
Another thing to note is that exclusion commands cannot pass through repeaters, unlike most other Z-Wave commands. Let’s go ahead and test for this, as well as for interference from other switches by trying to bring the Hub within 10 feet (it may need to be closer than this even) and trying the exclusion process for those switches again at that distance.
Please let me know what time you try to bring the Hub closer to the switch and begin General Device Exclusion. This way I can take a look in the event logs at what activity happened in your Z-Wave network at that time. Looking forward to hearing back from you.
My reply:
Thank you. That did the trick.
One of the devices paired right away with the hub closer. The other I had to do an exclusion on first and it did find an ‘unknown device’ to exclude this time. It then paired.
What threw me is I have other devices quite a bit further from the hub’s usual place. But, what was different this time is I was activating 3 devices at a time. I believe I have usually installed one at a time.
Things seem okay now. The hub is back in it’s normal place and all are paired and are responding to commands.
Now I can get on with the remaining 9 devices I have. Thanks Lowe’s.