I just corrected this to melee thralls though I haven’t checked it thoroughly enough.
I’ve had archers attack the rhino king successfully, but melee might have a swing and then they stop.
My base is outside Sepermeru where I get the occasional scorpions (small and medium size) and rhinos.
Scorpions get consistently attacks, but I’m mostly on my own with the rhinos.
I’m assuming the no lock on and no melee is related.