So the problem is that when FTL sees the client and tries to resolve the host names, it is still unknown (12:22). Only later, your script picks up the host name, FTL is aware of it (12:28).
It shouldn't. Imagine all the devices which do not register a proper hostname. I wouldn't want my Pi-hole statistics to be spammed by PTR requests for all these devices every minute. How could it know that resolving the client would now succeed (without doctoring the hosts file itself)?
What I don't understand here is that my FTL seems to re-query the hostnames for all clients again at every full hour - presumably to check for updated or new host names (like in your case).
@jpgpi250 Do you have such logging at 13:00 ?
@DL6ER For confirmation of rechecking all host names once every full hour.
edit
Found confirmation in a user report here: