@Bridget_WH,
The devices should be able to reconnect after the device is completely removed. I would check to make sure that the device is not connected to the network using a different IP address. Are you able to see the device in your list of offline devices?
I would highly recommend forgetting and reconnecting to the Wi-Fi network on the problem devices. This will allow the device and router to have a handshake and communicate details.Do the devices show that they are in fact, connected to the network?
You may consider rebooting your network after deleting the entries to force the reconnect. However, we don't really recommend rebooting mesh networks haphazardly.