Robotic Attack Drones despawning?

[Caraise Link]

At first I thought they were just despawning on a timer, as with the defender drones and such, until I realized they would only despawn after I was within roughly viewing distance. Watching them on radar, I've noticed that they stop moving after I've been gone a while, but will still rush in to attack any bugs in the vicinity. If I get close after they've stopped moving, though, they'll rapidly start disappearing. Usually they're gone fast enough that I don't actually see them, even with the camera zoomed out all the way, though one time I could drive up and park beside one before it, too, vanished into the ether. Not sure what the difference is, can't reproduce.

This really doesn't appear to be intended behavior. I looked through prototypes\entities\drone.lua to see if they had any kind of despawn flag set, but other than being flagged with "placeable-player" and "placeable-enemy" rather than "placeable-neutral", it doesn't seem conspicuously different from a tank with some AI settings. I'm guessing this is a bug, but I'm not really sure?

[bobingabout]

I'd go with a bug.

They're basically a "unit" type, same as a biter, or spitter. so any recent changes to biters and spitters likely applies to my attack drones too.
Although this is then a "Bug" for my attack drones, it is likely intended house cleaning behaviour for biters adversely effecting them.

Feel free to repost this in the bug reporting subforum.