What does this mean?
This is an LIFX A19 bulb and the firmware is up to date.
Assuming you're using @rob's LIFX App/Drivers - this is just an indication that the polling to keep Hubitat in sync with the actual bulb state is not getting a response from the bulb. Could be the bulb is on the edge of your wifi, and has a weak signal (it might receive commands just fine, but responses don't make it back to the AP) - or something else entirely.
@dkilgore90 had one answer. Another part of the answer is to check the IP address of your device on Hubitat versus what is listed on you router.
To add to @djgutheinz's answer, which btw, I think is very likely, I would also suggest making sure that the device hasn't been turned off at the switch, or unscrewed from the socket.
Thanks for the replies.
The lights are working fine so I'm just curious.
Both have fixed IP addresses and are in the same fixture twenty feet from the access point with a very strong connection.
If you have the code, look at poll or refresh. One is running every 1 minute and the command being sent to the device may be erroneous (and the device ignores the message with no response).