Thing is, none of these clients show up in the DCHP lease list. Or in the active clients. Or in the offline clients. Is this a bug or something? Like if it was actually connected to the network wouldn't it be showing there?
This is what I would assume man. in the mobile app you can see offline devices which basically lists everything that was once connected if not shown in the current client list. Anything that ever once connected will be listed there and greyed out and you can click on them and check the mac's. Have a look there. You can also delete all related settings on the router for each specific device there, say a certain device on your network is having issues connecting. Or if you want the router to forget its settings. Or just delete it off the list and see if they reappear. I can't find a similar way to do this from the web gui interestingly enough. I don't like the idea of using a mobile app for security purposes but it comes in handy and is convenient.
I 2nd the idea to put whitelist macfilter on which might help you sanitize it. MY windows and android devices don't use random macs. but what I also do is hide the ssid along with mac filtering setting them up to connect to hidden device. then mac and ip bind each 5g device in the router settings. I do this simply because I use merlin policy rules and want the wan devices to not change ip and it also helps to keep things organized and accounted for. You will also probably lessen random connections by hiding it.
I do have a linux laptop that at first randomized the mac address and the router will identify it as "anonymous" device in the offline list because it had no hostname either I guess. Or it recognized the same hostname changing mac's. But that will become flooded too. The router usually will keep the same ip for the same mac, but on very rare occasions it will change, which is why I use the binding option.
On another note I got over 30 wifi devices on my network sometimes and my logs are flooded with entries like yours. If you search around they drive alot of people nuts. I think they are debug entries that shouldn't even be showing and I wouldn't doubt they show wrong. I also see mac's I don't recognize alot and just assume its my neighbors or people walking by. I just ignore them now lol. Only time I focus on them, is when I see a single device flooding it over and over. then I will investigate. For example i saw one specific mac really flooding it once, found out it was my viziocast tv that does it when eco mode is on. Otherwise I pay them no mind.